[TD-2036] refactor code

src/client/src/tscUtil.c

@@ -71,7 +71,8 @@ void tsSetSTableQueryCond(STagCond* pTagCond, uint64_t uid, SBufferWriter* bw) {
 }
 
 bool tscQueryTags(SQueryInfo* pQueryInfo) {
-  for (int32_t i = 0; i < pQueryInfo->fieldsInfo.numOfOutput; ++i) {
+  int32_t numOfCols = tscSqlExprNumOfExprs(pQueryInfo);
+  for (int32_t i = 0; i < numOfCols; ++i) {
     SSqlExpr* pExpr = tscSqlExprGet(pQueryInfo, i);
     int32_t functId = pExpr->functionId;
 
@@ -201,13 +202,9 @@ bool tscIsProjectionQuery(SQueryInfo* pQueryInfo) {
 
 bool tscIsPointInterpQuery(SQueryInfo* pQueryInfo) {
   size_t size = tscSqlExprNumOfExprs(pQueryInfo);
-  
   for (int32_t i = 0; i < size; ++i) {
     SSqlExpr* pExpr = tscSqlExprGet(pQueryInfo, i);
     assert(pExpr != NULL);
-//    if (pExpr == NULL) {
-//      return false;
-//    }
 
     int32_t functionId = pExpr->functionId;
     if (functionId == TSDB_FUNC_TAG) {