Merge pull request #15153 from taosdata/fix/TD-17511

fix(query): forbid use null as input for first/last/last_row

source/libs/function/src/builtins.c

@@ -1425,6 +1425,17 @@ static int32_t translateIrate(SFunctionNode* pFunc, char* pErrBuf, int32_t len)
 }
 
 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);
+
+  for (int32_t i = 0; i < numOfParams; ++i) {
+    uint8_t nodeType = nodeType(nodesListGetNode(pFunc->pParameterList, i));
+    uint8_t paraType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, i))->resType.type;
+    if (IS_NULL_TYPE(paraType) && QUERY_NODE_VALUE == nodeType) {
+      return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
+    }
+  }
+
   pFunc->node.resType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, 0))->resType;
   return TSDB_CODE_SUCCESS;
 }
@@ -1435,6 +1446,15 @@ static int32_t translateFirstLastImpl(SFunctionNode* pFunc, char* pErrBuf, int32
   uint8_t paraType = ((SExprNode*)pPara)->resType.type;
   int32_t paraBytes = ((SExprNode*)pPara)->resType.bytes;
   if (isPartial) {
+    int32_t numOfParams = LIST_LENGTH(pFunc->pParameterList);
+    for (int32_t i = 0; i < numOfParams; ++i) {
+      uint8_t nodeType = nodeType(nodesListGetNode(pFunc->pParameterList, i));
+      uint8_t pType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, i))->resType.type;
+      if (IS_NULL_TYPE(pType) && QUERY_NODE_VALUE == nodeType) {
+        return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
+      }
+    }
+
     pFunc->node.resType =
         (SDataType){.bytes = getFirstLastInfoSize(paraBytes) + VARSTR_HEADER_SIZE, .type = TSDB_DATA_TYPE_BINARY};
   } else {

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

@@ -221,7 +221,7 @@ class TDTestCase:
         tdSql.execute("use testdb")
 
         # bug need fix
-        tdSql.query("select last_row(c1 ,NULL) from testdb.t1")
+        tdSql.error("select last_row(c1 ,NULL) from testdb.t1")
 
         error_sql_lists = [
             "select last_row from testdb.t1",