diff --git a/src/client/src/tscLocalMerge.c b/src/client/src/tscLocalMerge.c
index 77162a64b071e4079a802c15858577b126312bba..4a894f8008eb9071c7769e47db2c2fe672ebbb69 100644
--- a/src/client/src/tscLocalMerge.c
+++ b/src/client/src/tscLocalMerge.c
@@ -570,7 +570,7 @@ static int32_t createOrderDescriptor(tOrderDescriptor **pOrderDesc, SSqlCmd *pCm
   if (numOfGroupByCols > 0) {
 
     if (pQueryInfo->groupbyExpr.numOfGroupCols > 0) {
-      int32_t numOfInternalOutput = tscSqlExprNumOfExprs(pQueryInfo);
+      int32_t numOfInternalOutput = (int32_t) tscSqlExprNumOfExprs(pQueryInfo);
       int32_t startCols = numOfInternalOutput - pQueryInfo->groupbyExpr.numOfGroupCols;
 
       // the last "pQueryInfo->groupbyExpr.numOfGroupCols" columns are order-by columns