enh(query): support sum(NULL), max(NULL), min(NULL)

include/common/ttypes.h

@@ -179,6 +179,8 @@ typedef struct {
     }                                          \
   } while (0)
 
+//TODO: use varchar(0) to represent NULL type
+#define IS_NULL_TYPE(_t)             ((_t) == TSDB_DATA_TYPE_NULL)
 #define IS_SIGNED_NUMERIC_TYPE(_t)   ((_t) >= TSDB_DATA_TYPE_TINYINT && (_t) <= TSDB_DATA_TYPE_BIGINT)
 #define IS_UNSIGNED_NUMERIC_TYPE(_t) ((_t) >= TSDB_DATA_TYPE_UTINYINT && (_t) <= TSDB_DATA_TYPE_UBIGINT)
 #define IS_FLOAT_TYPE(_t)            ((_t) == TSDB_DATA_TYPE_FLOAT || (_t) == TSDB_DATA_TYPE_DOUBLE)

source/common/src/tdatablock.c

@@ -322,7 +322,9 @@ int32_t colDataAssign(SColumnInfoData* pColumnInfoData, const SColumnInfoData* p
     }
 
     pColumnInfoData->pData = tmp;
-    memcpy(pColumnInfoData->pData, pSource->pData, pSource->info.bytes * numOfRows);
+    if (pColumnInfoData->info.type != TSDB_DATA_TYPE_NULL) {
+      memcpy(pColumnInfoData->pData, pSource->pData, pSource->info.bytes * numOfRows);
+    }
   }
 
   pColumnInfoData->hasNull = pSource->hasNull;

source/libs/function/src/builtins.c

@@ -46,8 +46,10 @@ static int32_t translateInOutNum(SFunctionNode* pFunc, char* pErrBuf, int32_t le
   }
 
   uint8_t paraType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, 0))->resType.type;
-  if (!IS_NUMERIC_TYPE(paraType)) {
+  if (!IS_NUMERIC_TYPE(paraType) && !IS_NULL_TYPE(paraType)) {
     return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
+  } else if (IS_NULL_TYPE(paraType)) {
+    paraType = TSDB_DATA_TYPE_BIGINT;
   }
 
   pFunc->node.resType = (SDataType){.bytes = tDataTypes[paraType].bytes, .type = paraType};
@@ -114,18 +116,19 @@ static int32_t translateSum(SFunctionNode* pFunc, char* pErrBuf, int32_t len) {
   }
 
   uint8_t paraType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, 0))->resType.type;
-  if (!IS_NUMERIC_TYPE(paraType)) {
+  if (!IS_NUMERIC_TYPE(paraType) && !IS_NULL_TYPE(paraType)) {
     return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
   }
 
   uint8_t resType = 0;
-  if (IS_SIGNED_NUMERIC_TYPE(paraType) || paraType == TSDB_DATA_TYPE_BOOL) {
+  if (IS_SIGNED_NUMERIC_TYPE(paraType) || TSDB_DATA_TYPE_BOOL == paraType || IS_NULL_TYPE(paraType)) {
     resType = TSDB_DATA_TYPE_BIGINT;
   } else if (IS_UNSIGNED_NUMERIC_TYPE(paraType)) {
     resType = TSDB_DATA_TYPE_UBIGINT;
   } else if (IS_FLOAT_TYPE(paraType)) {
     resType = TSDB_DATA_TYPE_DOUBLE;
   }
+
   pFunc->node.resType = (SDataType){.bytes = tDataTypes[resType].bytes, .type = resType};
   return TSDB_CODE_SUCCESS;
 }

source/libs/function/src/builtinsimpl.c

@@ -255,7 +255,7 @@ int32_t functionFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock) {
   SColumnInfoData* pCol = taosArrayGet(pBlock->pDataBlock, slotId);
 
   SResultRowEntryInfo* pResInfo = GET_RES_INFO(pCtx);
-  pResInfo->isNullRes = (pResInfo->numOfRes == 0) ? 1 : 0;
+  //pResInfo->isNullRes = (pResInfo->numOfRes == 0) ? 1 : 0;
 
   char* in = GET_ROWCELL_INTERBUF(pResInfo);
   colDataAppend(pCol, pBlock->info.rows, in, pResInfo->isNullRes);
@@ -377,11 +377,17 @@ int32_t sumFunction(SqlFunctionCtx* pCtx) {
 
   // Only the pre-computing information loaded and actual data does not loaded
   SInputColumnInfoData* pInput = &pCtx->input;
-  SColumnDataAgg*       pAgg = pInput->pColumnDataAgg[0];
-  int32_t               type = pInput->pData[0]->info.type;
+  SColumnDataAgg*       pAgg   = pInput->pColumnDataAgg[0];
+  int32_t               type   = pInput->pData[0]->info.type;
 
   SSumRes* pSumRes = GET_ROWCELL_INTERBUF(GET_RES_INFO(pCtx));
 
+  if (IS_NULL_TYPE(type)) {
+    GET_RES_INFO(pCtx)->isNullRes = 1;
+    numOfElem = 1;
+    goto _sum_over;
+  }
+
   if (pInput->colDataAggIsSet) {
     numOfElem = pInput->numOfRows - pAgg->numOfNull;
     ASSERT(numOfElem >= 0);
@@ -426,6 +432,7 @@ int32_t sumFunction(SqlFunctionCtx* pCtx) {
     }
   }
 
+_sum_over:
   // data in the check operation are all null, not output
   SET_VAL(GET_RES_INFO(pCtx), numOfElem, 1);
   return TSDB_CODE_SUCCESS;
@@ -782,6 +789,12 @@ int32_t doMinMaxHelper(SqlFunctionCtx* pCtx, int32_t isMinFunc) {
   SResultRowEntryInfo* pResInfo = GET_RES_INFO(pCtx);
   SMinmaxResInfo *pBuf = GET_ROWCELL_INTERBUF(pResInfo);
 
+  if (IS_NULL_TYPE(type)) {
+    GET_RES_INFO(pCtx)->isNullRes = 1;
+    numOfElems = 1;
+    goto _min_max_over;
+  }
+
   // data in current data block are qualified to the query
   if (pInput->colDataAggIsSet) {
     numOfElems = pInput->numOfRows - pAgg->numOfNull;
@@ -1202,6 +1215,7 @@ int32_t doMinMaxHelper(SqlFunctionCtx* pCtx, int32_t isMinFunc) {
     }
   }
 
+_min_max_over:
   return numOfElems;
 }
 
@@ -1234,9 +1248,9 @@ int32_t minmaxFunctionFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock) {
 
   if (pCol->info.type == TSDB_DATA_TYPE_FLOAT) {
     float v = *(double*) &pRes->v;
-    colDataAppend(pCol, currentRow, (const char*)&v, false);
+    colDataAppend(pCol, currentRow, (const char*)&v, pEntryInfo->isNullRes);
   } else {
-    colDataAppend(pCol, currentRow, (const char*)&pRes->v, false);
+    colDataAppend(pCol, currentRow, (const char*)&pRes->v, pEntryInfo->isNullRes);
   }
 
   setSelectivityValue(pCtx, pBlock, &pRes->tuplePos, currentRow);