fix(query): diff function first param can only be column

TD-16067

source/libs/function/src/builtins.c

@@ -675,32 +675,41 @@ static int32_t translateUnique(SFunctionNode* pFunc, char* pErrBuf, int32_t len)
 }
 
 static int32_t translateDiff(SFunctionNode* pFunc, char* pErrBuf, int32_t len) {
-  int32_t paraLen = LIST_LENGTH(pFunc->pParameterList);
-  if (paraLen == 0 || paraLen > 2) {
+  int32_t numOfParams = LIST_LENGTH(pFunc->pParameterList);
+  if (numOfParams == 0 || numOfParams > 2) {
     return invaildFuncParaNumErrMsg(pErrBuf, len, pFunc->functionName);
   }
 
-  //param1
-  SNode* pParamNode1 = nodesListGetNode(pFunc->pParameterList, 1);
-  if (QUERY_NODE_VALUE != nodeType(pParamNode1)) {
-    return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
+  //param0
+  SNode* pParamNode0 = nodesListGetNode(pFunc->pParameterList, 0);
+  if (nodeType(pParamNode0) != QUERY_NODE_COLUMN) {
+    return buildFuncErrMsg(pErrBuf, len, TSDB_CODE_FUNC_FUNTION_ERROR,
+                           "The first parameter of DIFF function can only be column");
   }
 
-  SValueNode* pValue = (SValueNode*)pParamNode1;
-  if (pValue->datum.i != 0 && pValue->datum.i != 1) {
-    return buildFuncErrMsg(pErrBuf, len, TSDB_CODE_FUNC_FUNTION_ERROR,
-                           "Second parameter of DIFF function should be only 0 or 1");
+  uint8_t colType = ((SExprNode*)nodesListGetNode(pFunc->pParameterList, 0))->resType.type;
+  if (!IS_SIGNED_NUMERIC_TYPE(colType) && !IS_FLOAT_TYPE(colType) &&
+      TSDB_DATA_TYPE_BOOL != colType) {
+    return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
   }
 
-  pValue->notReserved = true;
+  //param1
+  if (numOfParams == 2) {
+    SNode* pParamNode1 = nodesListGetNode(pFunc->pParameterList, 1);
+    if (QUERY_NODE_VALUE != nodeType(pParamNode1)) {
+      return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
+    }
 
-  //param0
-  SExprNode* p1 = (SExprNode*)nodesListGetNode(pFunc->pParameterList, 0);
-  if (!IS_SIGNED_NUMERIC_TYPE(p1->resType.type) && !IS_FLOAT_TYPE(p1->resType.type) &&
-      TSDB_DATA_TYPE_BOOL != p1->resType.type) {
-    return invaildFuncParaTypeErrMsg(pErrBuf, len, pFunc->functionName);
+    SValueNode* pValue = (SValueNode*)pParamNode1;
+    if (pValue->datum.i != 0 && pValue->datum.i != 1) {
+      return buildFuncErrMsg(pErrBuf, len, TSDB_CODE_FUNC_FUNTION_ERROR,
+                             "Second parameter of DIFF function should be only 0 or 1");
+    }
+
+    pValue->notReserved = true;
   }
-  pFunc->node.resType = p1->resType;
+
+  pFunc->node.resType = (SDataType){.bytes = tDataTypes[colType].bytes, .type = colType};
   return TSDB_CODE_SUCCESS;
 }