diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index a0089379a9c71434ed1a7aa7547724145241b89f..a5990abf32f1169cb59535689d901f1ec0b9d09a 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -321,6 +321,9 @@ TAOS_FIELD *taos_fetch_fields(TAOS_RES *res) {
   if (pSql == NULL || pSql->signature != pSql) return 0;
 
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(&pSql->cmd, 0);
+  if(NULL == pQueryInfo) {
+    return NULL;  
+  }
   return pQueryInfo->fieldsInfo.pFields;
 }