diff --git a/src/client/src/tscSub.c b/src/client/src/tscSub.c
index e44f88189fb5f7c353228bc26cabee40cf38aff7..b3d18f50114cd88e75e559323fed8c7d6f934289 100644
--- a/src/client/src/tscSub.c
+++ b/src/client/src/tscSub.c
@@ -149,7 +149,6 @@ static SSub* tscCreateSubscription(STscObj* pObj, const char* topic, const char*
     goto fail;
   }
 
-  strtolower(pSql->sqlstr, pSql->sqlstr);
   pRes->qId = 0;
   pRes->numOfRows = 1;
   pCmd->resColumnId = TSDB_RES_COL_ID;