diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index b9fe5e72476da96138ca4b010ca275ce2b4c80b9..d105c577db1b2c8d21ec16286dd19c1ca722e721 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -4562,7 +4562,7 @@ int32_t parseFillClause(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, SQuerySQL* pQuery
   }
 
   size_t numOfExprs = tscSqlExprNumOfExprs(pQueryInfo);
-  for(size_t i = 0; i < numOfExprs; ++i) {
+  for(int32_t i = 0; i < numOfExprs; ++i) {
     SSqlExpr* pExpr = tscSqlExprGet(pQueryInfo, i);
     if (pExpr->functionId == TSDB_FUNC_TOP || pExpr->functionId == TSDB_FUNC_BOTTOM) {
       return invalidSqlErrMsg(tscGetErrorMsgPayload(pCmd), msg3);