Merge pull request #21329 from taosdata/feat/TD-21187

feat(query): interp support ignore null value opition

docs/en/12-taos-sql/10-function.md

@@ -867,10 +867,16 @@ FIRST(expr)
 ### INTERP
 
 ```sql
-INTERP(expr)
+INTERP(expr [, ignore_null_values])
+
+ignore_null_values: {
+    0
+  | 1
+}
 ```
 
-**Description**: The value that matches the specified timestamp range is returned, if existing; or an interpolation value is returned.
+**Description**: The value that matches the specified timestamp range is returned, if existing; or an interpolation value is returned. The value of `ignore_null_values` can be 0 or 1, 1 means null values are ignored. The default value of this parameter is 0.
+
 
 **Return value type**: Same as the column being operated upon
 

docs/zh/12-taos-sql/10-function.md

@@ -869,10 +869,15 @@ FIRST(expr)
 ### INTERP
 
 ```sql
-INTERP(expr)
+INTERP(expr [, ignore_null_values])
+
+ignore_null_values: {
+    0
+  | 1
+}
 ```
 
-**功能说明**：返回指定时间截面指定列的记录值或插值。
+**功能说明**：返回指定时间截面指定列的记录值或插值。ignore_null_values 参数的值可以是 0 或 1，为 1 时表示忽略 NULL 值, 缺省值为0。
 
 **返回数据类型**：同字段类型。
 

source/libs/executor/src/timesliceoperator.c

@@ -209,6 +209,45 @@ static bool isGroupKeyFunc(SExprInfo* pExprInfo) {
   return (functionType == FUNCTION_TYPE_GROUP_KEY);
 }
 
+static bool getIgoreNullRes(SExprSupp* pExprSup) {
+  for (int32_t i = 0; i < pExprSup->numOfExprs; ++i) {
+    SExprInfo* pExprInfo = &pExprSup->pExprInfo[i];
+
+    if (isInterpFunc(pExprInfo)) {
+      for (int32_t j = 0; j < pExprInfo->base.numOfParams; ++j) {
+        SFunctParam *pFuncParam = &pExprInfo->base.pParam[j];
+        if (pFuncParam->type == FUNC_PARAM_TYPE_VALUE) {
+          return pFuncParam->param.i ? true : false;
+        }
+      }
+    }
+  }
+
+  return false;
+}
+
+static bool checkNullRow(SExprSupp* pExprSup, SSDataBlock* pSrcBlock, int32_t index, bool ignoreNull) {
+  if (!ignoreNull) {
+    return false;
+  }
+
+  for (int32_t j = 0; j < pExprSup->numOfExprs; ++j) {
+    SExprInfo* pExprInfo = &pExprSup->pExprInfo[j];
+
+    if (isInterpFunc(pExprInfo)) {
+      int32_t       srcSlot = pExprInfo->base.pParam[0].pCol->slotId;
+      SColumnInfoData* pSrc = taosArrayGet(pSrcBlock->pDataBlock, srcSlot);
+
+      if (colDataIsNull_s(pSrc, index)) {
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+
 static bool genInterpolationResult(STimeSliceOperatorInfo* pSliceInfo, SExprSupp* pExprSup, SSDataBlock* pResBlock,
                                    SSDataBlock* pSrcBlock, int32_t index, bool beforeTs) {
   int32_t rows = pResBlock->info.rows;
@@ -602,7 +641,7 @@ static int32_t resetKeeperInfo(STimeSliceOperatorInfo* pInfo) {
 }
 
 static void doTimesliceImpl(SOperatorInfo* pOperator, STimeSliceOperatorInfo* pSliceInfo, SSDataBlock* pBlock,
-                            SExecTaskInfo* pTaskInfo) {
+                            SExecTaskInfo* pTaskInfo, bool ignoreNull) {
   SSDataBlock* pResBlock = pSliceInfo->pRes;
   SInterval*   pInterval = &pSliceInfo->interval;
 
@@ -615,6 +654,10 @@ static void doTimesliceImpl(SOperatorInfo* pOperator, STimeSliceOperatorInfo* pS
       T_LONG_JMP(pTaskInfo->env, TSDB_CODE_FUNC_DUP_TIMESTAMP);
     }
 
+    if (checkNullRow(&pOperator->exprSupp, pBlock, i, ignoreNull)) {
+      continue;
+    }
+
     if (pSliceInfo->current > pSliceInfo->win.ekey) {
       break;
     }
@@ -744,6 +787,7 @@ static SSDataBlock* doTimeslice(SOperatorInfo* pOperator) {
   STimeSliceOperatorInfo* pSliceInfo = pOperator->info;
   SSDataBlock*            pResBlock = pSliceInfo->pRes;
   SExprSupp*              pSup = &pOperator->exprSupp;
+  bool                    ignoreNull = getIgoreNullRes(pSup);
 
   int32_t        order = TSDB_ORDER_ASC;
   SInterval*     pInterval = &pSliceInfo->interval;
@@ -754,7 +798,7 @@ static SSDataBlock* doTimeslice(SOperatorInfo* pOperator) {
   while (1) {
     if (pSliceInfo->pNextGroupRes != NULL) {
       setInputDataBlock(pSup, pSliceInfo->pNextGroupRes, order, MAIN_SCAN, true);
-      doTimesliceImpl(pOperator, pSliceInfo, pSliceInfo->pNextGroupRes, pTaskInfo);
+      doTimesliceImpl(pOperator, pSliceInfo, pSliceInfo->pNextGroupRes, pTaskInfo, ignoreNull);
       copyPrevGroupKey(&pOperator->exprSupp, pSliceInfo->pPrevGroupKey, pSliceInfo->pNextGroupRes);
       pSliceInfo->pNextGroupRes = NULL;
     }
@@ -788,7 +832,7 @@ static SSDataBlock* doTimeslice(SOperatorInfo* pOperator) {
 
       // the pDataBlock are always the same one, no need to call this again
       setInputDataBlock(pSup, pBlock, order, MAIN_SCAN, true);
-      doTimesliceImpl(pOperator, pSliceInfo, pBlock, pTaskInfo);
+      doTimesliceImpl(pOperator, pSliceInfo, pBlock, pTaskInfo, ignoreNull);
       copyPrevGroupKey(&pOperator->exprSupp, pSliceInfo->pPrevGroupKey, pBlock);
     }
 

source/libs/function/src/builtins.c

@@ -1568,17 +1568,32 @@ static int32_t translateInterp(SFunctionNode* pFunc, char* pErrBuf, int32_t len)
   int32_t numOfParams = LIST_LENGTH(pFunc->pParameterList);
   uint8_t dbPrec = pFunc->node.resType.precision;
 
-  // if (1 != numOfParams && 3 != numOfParams && 4 != numOfParams) {
-  if (1 != numOfParams) {
+  if (2 < numOfParams) {
     return invaildFuncParaNumErrMsg(pErrBuf, len, pFunc->functionName);
   }
 
   uint8_t nodeType = nodeType(nodesListGetNode(pFunc->pParameterList, 0));
   uint8_t paraType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, 0))->resType.type;
-  if ((!IS_NUMERIC_TYPE(paraType) && !IS_BOOLEAN_TYPE(paraType))|| QUERY_NODE_VALUE == nodeType) {
+  if ((!IS_NUMERIC_TYPE(paraType) && !IS_BOOLEAN_TYPE(paraType)) || QUERY_NODE_VALUE == nodeType) {
     return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
   }
 
+  if (2 == numOfParams) {
+    nodeType = nodeType(nodesListGetNode(pFunc->pParameterList, 1));
+    paraType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, 1))->resType.type;
+    if (!IS_INTEGER_TYPE(paraType) || QUERY_NODE_VALUE != nodeType) {
+      return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
+    }
+
+    SValueNode* pValue = (SValueNode*)nodesListGetNode(pFunc->pParameterList, 1);
+    if (pValue->datum.i != 0 && pValue->datum.i != 1) {
+      return buildFuncErrMsg(pErrBuf, len, TSDB_CODE_FUNC_FUNTION_ERROR,
+                             "INTERP function second parameter should be 0/1");
+    }
+
+    pValue->notReserved = true;
+  }
+
 #if 0
   if (3 <= numOfParams) {
     int64_t timeVal[2] = {0};
@@ -1624,6 +1639,15 @@ static int32_t translateInterp(SFunctionNode* pFunc, char* pErrBuf, int32_t len)
   return TSDB_CODE_SUCCESS;
 }
 
+static EFuncReturnRows interpEstReturnRows(SFunctionNode* pFunc) {
+  int32_t numOfParams = LIST_LENGTH(pFunc->pParameterList);
+  if (1 < numOfParams && 1 == ((SValueNode*)nodesListGetNode(pFunc->pParameterList, 1))->datum.i) {
+    return FUNC_RETURN_ROWS_INDEFINITE;
+  } else {
+    return FUNC_RETURN_ROWS_N;
+  }
+}
+
 static int32_t translateFirstLast(SFunctionNode* pFunc, char* pErrBuf, int32_t len) {
   // forbid null as first/last input, since first(c0, null, 1) may have different number of input
   int32_t numOfParams = LIST_LENGTH(pFunc->pParameterList);
@@ -2484,7 +2508,8 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = {
     .getEnvFunc    = getSelectivityFuncEnv,
     .initFunc      = functionSetup,
     .processFunc   = NULL,
-    .finalizeFunc  = NULL
+    .finalizeFunc  = NULL,
+    .estimateReturnRowsFunc = interpEstReturnRows
   },
   {
     .name = "derivative",

source/libs/parser/src/parTranslater.c

@@ -1526,6 +1526,12 @@ static int32_t translateInterpFunc(STranslateContext* pCxt, SFunctionNode* pFunc
   if (pSelect->hasAggFuncs || pSelect->hasMultiRowsFunc || pSelect->hasIndefiniteRowsFunc) {
     return generateSyntaxErrMsg(&pCxt->msgBuf, TSDB_CODE_PAR_NOT_ALLOWED_FUNC);
   }
+
+  if (pSelect->hasInterpFunc && (FUNC_RETURN_ROWS_INDEFINITE == pSelect->returnRows || pSelect->returnRows != fmGetFuncReturnRows(pFunc))) {
+    return generateSyntaxErrMsgExt(&pCxt->msgBuf, TSDB_CODE_PAR_NOT_ALLOWED_FUNC,
+                                "%s ignoring null value options cannot be used when applying to multiple columns", pFunc->functionName);
+  }
+
   if (NULL != pSelect->pWindow || NULL != pSelect->pGroupByList) {
     return generateSyntaxErrMsgExt(&pCxt->msgBuf, TSDB_CODE_PAR_NOT_ALLOWED_FUNC,
                                    "%s function is not supported in window query or group query", pFunc->functionName);
@@ -1726,7 +1732,10 @@ static void setFuncClassification(SNode* pCurrStmt, SFunctionNode* pFunc) {
     if (fmIsIndefiniteRowsFunc(pFunc->funcId)) {
       pSelect->hasIndefiniteRowsFunc = true;
       pSelect->returnRows = fmGetFuncReturnRows(pFunc);
+    } else if (fmIsInterpFunc(pFunc->funcId)) {
+      pSelect->returnRows = fmGetFuncReturnRows(pFunc);
     }
+
     pSelect->hasMultiRowsFunc = pSelect->hasMultiRowsFunc ? true : fmIsMultiRowsFunc(pFunc->funcId);
     if (fmIsSelectFunc(pFunc->funcId)) {
       pSelect->hasSelectFunc = true;

tests/system-test/2-query/interp.py

@@ -26,6 +26,12 @@ class TDTestCase:
         ctbname3 = "ctb3"
         num_of_ctables = 3
 
+        tbname_null = "tb_null"
+        ctbname1_null = "ctb1_null"
+        ctbname2_null = "ctb2_null"
+        ctbname3_null = "ctb3_null"
+        stbname_null = "stb_null"
+
         tdSql.prepare()
 
         tdLog.printNoPrefix("==========step1:create table")
@@ -2943,8 +2949,1075 @@ class TDTestCase:
         tdSql.error(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname} range('2020-02-01 00:00:00', '2020-02-01 00:00:18') every(1s) fill(null)")
         tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname} partition by tbname range('2020-02-01 00:00:00', '2020-02-01 00:00:18') every(1s) fill(null)")
 
+        tdLog.printNoPrefix("======step 14: test interp ignore null values")
+        tdSql.execute(
+            f'''create table if not exists {dbname}.{tbname_null}
+            (ts timestamp, c0 int, c1 float, c2 bool)
+            '''
+        )
+
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:01', 1,    1.0,  true)")
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:02', NULL, NULL, NULL)")
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:03', 3,    3.0,  false)")
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:04', NULL, NULL, NULL)")
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:05', NULL, NULL, NULL)")
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:06', 6,    6.0,  true)")
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:07', NULL, NULL, NULL)")
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:08', 8,    8.0,  false)")
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:09', 9,    9.0,  true)")
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:10', NULL, NULL, NULL)")
+        tdSql.execute(f"insert into {dbname}.{tbname_null} values ('2020-02-02 00:00:11', NULL, NULL, NULL)")
+
+        tdSql.execute(
+            f'''create table if not exists {dbname}.{stbname_null}
+            (ts timestamp, c0 int, c1 float, c2 bool) tags (t0 int)
+            '''
+        )
+
+        tdSql.execute(
+            f'''create table if not exists {dbname}.{ctbname1_null} using {dbname}.{stbname_null} tags(1)
+            '''
+        )
+
+        tdSql.execute(
+            f'''create table if not exists {dbname}.{ctbname2_null} using {dbname}.{stbname_null} tags(2)
+            '''
+        )
+
+        tdSql.execute(
+            f'''create table if not exists {dbname}.{ctbname3_null} using {dbname}.{stbname_null} tags(3)
+            '''
+        )
+
+        tdSql.execute(f"insert into {dbname}.{ctbname1_null} values ('2020-02-01 00:00:01', 1, 1.0, true)")
+        tdSql.execute(f"insert into {dbname}.{ctbname1_null} values ('2020-02-01 00:00:07', NULL, NULL, NULL)")
+        tdSql.execute(f"insert into {dbname}.{ctbname1_null} values ('2020-02-01 00:00:13', 13, 13.0, false)")
+
+        tdSql.execute(f"insert into {dbname}.{ctbname2_null} values ('2020-02-01 00:00:03', NULL, NULL, NULL)")
+        tdSql.execute(f"insert into {dbname}.{ctbname2_null} values ('2020-02-01 00:00:09', 9, 9.0, true)")
+        tdSql.execute(f"insert into {dbname}.{ctbname2_null} values ('2020-02-01 00:00:15', 15, 15.0, false)")
+
+        tdSql.execute(f"insert into {dbname}.{ctbname3_null} values ('2020-02-01 00:00:05', NULL, NULL, NULL)")
+        tdSql.execute(f"insert into {dbname}.{ctbname3_null} values ('2020-02-01 00:00:11', NULL, NULL, NULL)")
+        tdSql.execute(f"insert into {dbname}.{ctbname3_null} values ('2020-02-01 00:00:17', NULL, NULL, NULL)")
+
+        # fill null
+        # normal table
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(NULL)")
+
+        tdSql.checkRows(11)
+        for i in range (11):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(NULL)")
+
+        tdSql.checkRows(11)
+        for i in range (11):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 1) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(NULL)")
+
+        tdSql.checkRows(11)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, False)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, True)
+        tdSql.checkData(5,  1, False)
+        tdSql.checkData(6,  1, True)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, False)
+        tdSql.checkData(9,  1, True)
+        tdSql.checkData(10, 1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{tbname_null} where c0 is not null range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(NULL)")
+
+        tdSql.checkRows(11)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, False)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, True)
+        tdSql.checkData(5,  1, False)
+        tdSql.checkData(6,  1, True)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, False)
+        tdSql.checkData(9,  1, True)
+        tdSql.checkData(10, 1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        # super table
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(NULL)")
+
+        tdSql.checkRows(9)
+        for i in range (9):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(NULL)")
+
+        tdSql.checkRows(9)
+        for i in range (9):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 1) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(NULL)")
+
+        tdSql.checkRows(9)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, True)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, False)
+        tdSql.checkData(5,  1, True)
+        tdSql.checkData(6,  1, False)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} where c0 is not null range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(NULL)")
+
+        tdSql.checkRows(9)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, True)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, False)
+        tdSql.checkData(5,  1, True)
+        tdSql.checkData(6,  1, False)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select tbname, _irowts, _isfilled, interp(c0, 1) from {dbname}.{stbname_null} partition by tbname range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(NULL)")
+
+        tdSql.checkRows(27)
+        for i in range(0, 9):
+            tdSql.checkData(i, 0, 'ctb1_null')
+
+        for i in range(9, 18):
+            tdSql.checkData(i, 0, 'ctb2_null')
+
+        for i in range(18, 27):
+            tdSql.checkData(i, 0, 'ctb3_null')
+
+        tdSql.checkData(0,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(8,  1, '2020-02-01 00:00:17.000')
+
+        tdSql.checkData(9,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(17, 1, '2020-02-01 00:00:17.000')
+
+        tdSql.checkData(18, 1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(26, 1, '2020-02-01 00:00:17.000')
+
+        tdSql.query(f"select tbname, _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} where c0 is not null partition by tbname range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(NULL)")
+
+        tdSql.checkRows(18)
+        for i in range(0, 9):
+            tdSql.checkData(i, 0, 'ctb1_null')
+
+        for i in range(9, 17):
+            tdSql.checkData(i, 0, 'ctb2_null')
+
+        tdSql.checkData(0,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(8,  1, '2020-02-01 00:00:17.000')
+
+        tdSql.checkData(9,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(17, 1, '2020-02-01 00:00:17.000')
+
+        # fill value
+        # normal table
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(value, 0)")
+
+        tdSql.checkRows(11)
+        for i in range (11):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(value, 0)")
+
+        tdSql.checkRows(11)
+        for i in range (11):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 1) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(value, 0)")
+
+        tdSql.checkRows(11)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, False)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, True)
+        tdSql.checkData(5,  1, False)
+        tdSql.checkData(6,  1, True)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, False)
+        tdSql.checkData(9,  1, True)
+        tdSql.checkData(10, 1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 0)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, 0)
+        tdSql.checkData(4,  2, 0)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, 0)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, 0)
+        tdSql.checkData(10, 2, 0)
+
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{tbname_null} where c0 is not null range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(value, 0)")
+
+        tdSql.checkRows(11)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, False)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, True)
+        tdSql.checkData(5,  1, False)
+        tdSql.checkData(6,  1, True)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, False)
+        tdSql.checkData(9,  1, True)
+        tdSql.checkData(10, 1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 0)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, 0)
+        tdSql.checkData(4,  2, 0)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, 0)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, 0)
+        tdSql.checkData(10, 2, 0)
+
+        # super table
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(value, 0)")
+
+        tdSql.checkRows(9)
+        for i in range (9):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(value, 0)")
+
+        tdSql.checkRows(9)
+        for i in range (9):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 1) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(value, 0)")
+
+        tdSql.checkRows(9)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, True)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, False)
+        tdSql.checkData(5,  1, True)
+        tdSql.checkData(6,  1, False)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 0)
+        tdSql.checkData(2,  2, 0)
+        tdSql.checkData(3,  2, 0)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, 0)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, 0)
+
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} where c0 is not null range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(value, 0)")
+
+        tdSql.checkRows(9)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, True)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, False)
+        tdSql.checkData(5,  1, True)
+        tdSql.checkData(6,  1, False)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 0)
+        tdSql.checkData(2,  2, 0)
+        tdSql.checkData(3,  2, 0)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, 0)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, 0)
+
+        tdSql.query(f"select tbname, _irowts, _isfilled, interp(c0, 1) from {dbname}.{stbname_null} partition by tbname range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(value, 0)")
+
+        tdSql.checkRows(27)
+        for i in range(0, 9):
+            tdSql.checkData(i, 0, 'ctb1_null')
+
+        for i in range(9, 18):
+            tdSql.checkData(i, 0, 'ctb2_null')
+
+        for i in range(18, 27):
+            tdSql.checkData(i, 0, 'ctb3_null')
+
+        tdSql.checkData(0,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(8,  1, '2020-02-01 00:00:17.000')
+
+        tdSql.checkData(9,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(17, 1, '2020-02-01 00:00:17.000')
+
+        tdSql.checkData(18, 1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(26, 1, '2020-02-01 00:00:17.000')
+
+        tdSql.query(f"select tbname, _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} where c0 is not null partition by tbname range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(value, 0)")
+
+        tdSql.checkRows(18)
+        for i in range(0, 9):
+            tdSql.checkData(i, 0, 'ctb1_null')
+
+        for i in range(9, 18):
+            tdSql.checkData(i, 0, 'ctb2_null')
+
+        tdSql.checkData(0,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(8,  1, '2020-02-01 00:00:17.000')
+
+        tdSql.checkData(9,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(17, 1, '2020-02-01 00:00:17.000')
+
+        # fill prev
+        # normal table
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(prev)")
+
+        tdSql.checkRows(11)
+        for i in range (11):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(prev)")
+
+        tdSql.checkRows(11)
+        for i in range (11):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 1) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(prev)")
+
+        tdSql.checkRows(11)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, False)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, True)
+        tdSql.checkData(5,  1, False)
+        tdSql.checkData(6,  1, True)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, False)
+        tdSql.checkData(9,  1, True)
+        tdSql.checkData(10, 1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 1)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, 3)
+        tdSql.checkData(4,  2, 3)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, 6)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, 9)
+        tdSql.checkData(10, 2, 9)
+
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{tbname_null} where c0 is not null range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(prev)")
+
+        tdSql.checkRows(11)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, False)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, True)
+        tdSql.checkData(5,  1, False)
+        tdSql.checkData(6,  1, True)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, False)
+        tdSql.checkData(9,  1, True)
+        tdSql.checkData(10, 1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 1)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, 3)
+        tdSql.checkData(4,  2, 3)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, 6)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, 9)
+        tdSql.checkData(10, 2, 9)
+
+        # super table
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(prev)")
+
+        tdSql.checkRows(9)
+        for i in range (9):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(prev)")
+
+        tdSql.checkRows(9)
+        for i in range (9):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 1) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(prev)")
+
+        tdSql.checkRows(9)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, True)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, False)
+        tdSql.checkData(5,  1, True)
+        tdSql.checkData(6,  1, False)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 1)
+        tdSql.checkData(2,  2, 1)
+        tdSql.checkData(3,  2, 1)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, 9)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, 15)
+
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} where c0 is not null range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(prev)")
+
+        tdSql.checkRows(9)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, True)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, False)
+        tdSql.checkData(5,  1, True)
+        tdSql.checkData(6,  1, False)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, True)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 1)
+        tdSql.checkData(2,  2, 1)
+        tdSql.checkData(3,  2, 1)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, 9)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, 15)
+
+        tdSql.query(f"select tbname, _irowts, _isfilled, interp(c0, 1) from {dbname}.{stbname_null} partition by tbname range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(prev)")
+
+        tdSql.checkRows(14)
+        for i in range(0, 9):
+            tdSql.checkData(i, 0, 'ctb1_null')
+
+        for i in range(9, 13):
+            tdSql.checkData(i, 0, 'ctb2_null')
+
+        tdSql.checkData(0,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(8,  1, '2020-02-01 00:00:17.000')
+
+        tdSql.checkData(9,  1, '2020-02-01 00:00:09.000')
+        tdSql.checkData(13, 1, '2020-02-01 00:00:17.000')
+
+        tdSql.query(f"select tbname, _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} where c0 is not null partition by tbname range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(prev)")
+
+        tdSql.checkRows(14)
+        for i in range(0, 9):
+            tdSql.checkData(i, 0, 'ctb1_null')
+
+        for i in range(9, 13):
+            tdSql.checkData(i, 0, 'ctb2_null')
+
+        tdSql.checkData(0,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(8,  1, '2020-02-01 00:00:17.000')
+
+        tdSql.checkData(9,  1, '2020-02-01 00:00:09.000')
+        tdSql.checkData(13, 1, '2020-02-01 00:00:17.000')
+
+        # fill next
+        # normal table
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(next)")
+
+        tdSql.checkRows(11)
+        for i in range (11):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(next)")
+
+        tdSql.checkRows(11)
+        for i in range (11):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 1) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(next)")
+
+        tdSql.checkRows(9)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, False)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, True)
+        tdSql.checkData(5,  1, False)
+        tdSql.checkData(6,  1, True)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 3)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, 6)
+        tdSql.checkData(4,  2, 6)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, 8)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{tbname_null} where c0 is not null range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(next)")
+
+        tdSql.checkRows(9)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, False)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, True)
+        tdSql.checkData(5,  1, False)
+        tdSql.checkData(6,  1, True)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 3)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, 6)
+        tdSql.checkData(4,  2, 6)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, 8)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+
+        # super table
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(next)")
+
+        tdSql.checkRows(9)
+        for i in range (9):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(next)")
+
+        tdSql.checkRows(9)
+        for i in range (9):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 1) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(next)")
+
+        tdSql.checkRows(8)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, True)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, False)
+        tdSql.checkData(5,  1, True)
+        tdSql.checkData(6,  1, False)
+        tdSql.checkData(7,  1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 9)
+        tdSql.checkData(2,  2, 9)
+        tdSql.checkData(3,  2, 9)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, 13)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} where c0 is not null range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(next)")
+
+        tdSql.checkRows(8)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, True)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, False)
+        tdSql.checkData(5,  1, True)
+        tdSql.checkData(6,  1, False)
+        tdSql.checkData(7,  1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 9)
+        tdSql.checkData(2,  2, 9)
+        tdSql.checkData(3,  2, 9)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, 13)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+
+        tdSql.query(f"select tbname, _irowts, _isfilled, interp(c0, 1) from {dbname}.{stbname_null} partition by tbname range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(next)")
+
+        tdSql.checkRows(15)
+        for i in range(0, 7):
+            tdSql.checkData(i, 0, 'ctb1_null')
+
+        for i in range(7, 15):
+            tdSql.checkData(i, 0, 'ctb2_null')
+
+        tdSql.checkData(0,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(6,  1, '2020-02-01 00:00:13.000')
+
+        tdSql.checkData(7,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(14, 1, '2020-02-01 00:00:15.000')
+
+        tdSql.query(f"select tbname, _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} where c0 is not null partition by tbname range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(next)")
+
+        tdSql.checkRows(15)
+        for i in range(0, 7):
+            tdSql.checkData(i, 0, 'ctb1_null')
+
+        for i in range(7, 15):
+            tdSql.checkData(i, 0, 'ctb2_null')
+
+        tdSql.checkData(0,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(6,  1, '2020-02-01 00:00:13.000')
+
+        tdSql.checkData(7,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(14, 1, '2020-02-01 00:00:15.000')
+
+        # fill linear
+        # normal table
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(linear)")
+
+        tdSql.checkRows(11)
+        for i in range (11):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(linear)")
+
+        tdSql.checkRows(11)
+        for i in range (11):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, None)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, None)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+        tdSql.checkData(9,  2, None)
+        tdSql.checkData(10, 2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 1) from {dbname}.{tbname_null} range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(linear)")
+
+        tdSql.checkRows(9)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, False)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, True)
+        tdSql.checkData(5,  1, False)
+        tdSql.checkData(6,  1, True)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 2)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, 4)
+        tdSql.checkData(4,  2, 5)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, 7)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{tbname_null} where c0 is not null range('2020-02-02 00:00:01', '2020-02-02 00:00:11') every(1s) fill(linear)")
+
+        tdSql.checkRows(9)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, False)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, True)
+        tdSql.checkData(5,  1, False)
+        tdSql.checkData(6,  1, True)
+        tdSql.checkData(7,  1, False)
+        tdSql.checkData(8,  1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 2)
+        tdSql.checkData(2,  2, 3)
+        tdSql.checkData(3,  2, 4)
+        tdSql.checkData(4,  2, 5)
+        tdSql.checkData(5,  2, 6)
+        tdSql.checkData(6,  2, 7)
+        tdSql.checkData(7,  2, 8)
+        tdSql.checkData(8,  2, 9)
+
+        # super table
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+
+        tdSql.checkRows(9)
+        for i in range (9):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+
+        tdSql.checkRows(9)
+        for i in range (9):
+          tdSql.checkData(i, 1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, None)
+        tdSql.checkData(2,  2, None)
+        tdSql.checkData(3,  2, None)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, None)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+        tdSql.checkData(8,  2, None)
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 1) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+
+        tdSql.checkRows(8)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, True)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, False)
+        tdSql.checkData(5,  1, True)
+        tdSql.checkData(6,  1, False)
+        tdSql.checkData(7,  1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 3)
+        tdSql.checkData(2,  2, 5)
+        tdSql.checkData(3,  2, 7)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, 11)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} where c0 is not null range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+
+        tdSql.checkRows(8)
+        tdSql.checkData(0,  1, False)
+        tdSql.checkData(1,  1, True)
+        tdSql.checkData(2,  1, True)
+        tdSql.checkData(3,  1, True)
+        tdSql.checkData(4,  1, False)
+        tdSql.checkData(5,  1, True)
+        tdSql.checkData(6,  1, False)
+        tdSql.checkData(7,  1, False)
+
+        tdSql.checkData(0,  2, 1)
+        tdSql.checkData(1,  2, 3)
+        tdSql.checkData(2,  2, 5)
+        tdSql.checkData(3,  2, 7)
+        tdSql.checkData(4,  2, 9)
+        tdSql.checkData(5,  2, 11)
+        tdSql.checkData(6,  2, 13)
+        tdSql.checkData(7,  2, 15)
+
+        tdSql.query(f"select tbname, _irowts, _isfilled, interp(c0, 1) from {dbname}.{stbname_null} partition by tbname range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+
+        tdSql.checkRows(11)
+        for i in range(0, 7):
+            tdSql.checkData(i, 0, 'ctb1_null')
+
+        for i in range(7, 11):
+            tdSql.checkData(i, 0, 'ctb2_null')
+
+        tdSql.checkData(0,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(6,  1, '2020-02-01 00:00:13.000')
+
+        tdSql.checkData(7,  1, '2020-02-01 00:00:09.000')
+        tdSql.checkData(10, 1, '2020-02-01 00:00:15.000')
+
+        tdSql.query(f"select tbname, _irowts, _isfilled, interp(c0) from {dbname}.{stbname_null} where c0 is not null partition by tbname range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+
+        tdSql.checkRows(11)
+        for i in range(0, 7):
+            tdSql.checkData(i, 0, 'ctb1_null')
+
+        for i in range(7, 11):
+            tdSql.checkData(i, 0, 'ctb2_null')
+
+        tdSql.checkData(0,  1, '2020-02-01 00:00:01.000')
+        tdSql.checkData(6,  1, '2020-02-01 00:00:13.000')
+
+        tdSql.checkData(7,  1, '2020-02-01 00:00:09.000')
+        tdSql.checkData(10, 1, '2020-02-01 00:00:15.000')
+
+        # multiple column with ignoring null value is not allowed
+
+        tdSql.query(f"select _irowts, _isfilled, interp(c0), interp(c1), interp(c2) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+        tdSql.query(f"select _irowts, _isfilled, interp(c0, 0), interp(c1, 0), interp(c2, 0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+        tdSql.query(f"select _irowts, _isfilled, interp(c0), interp(c1, 0), interp(c2) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+
+        tdSql.error(f"select _irowts, _isfilled, interp(c0), interp(c1, 1), interp(c2) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+        tdSql.error(f"select _irowts, _isfilled, interp(c0, 1), interp(c1, 0), interp(c2, 0) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+        tdSql.error(f"select _irowts, _isfilled, interp(c0), interp(c1, 0), interp(c2, 1) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+        tdSql.error(f"select _irowts, _isfilled, interp(c0, 1), interp(c1, 1), interp(c2, 1) from {dbname}.{stbname_null} range('2020-02-01 00:00:01', '2020-02-01 00:00:17') every(2s) fill(linear)")
+
+
 
-        tdLog.printNoPrefix("======step 14: test interp pseudo columns")
+        tdLog.printNoPrefix("======step 15: test interp pseudo columns")
         tdSql.error(f"select _irowts, c6 from {dbname}.{tbname}")
 
         tdLog.printNoPrefix("======step 15: test interp in nested query")