Merge pull request #5107 from taosdata/hotfix/TD-2904

fix mem leak

src/kit/taosdemo/taosdemo.c

@@ -908,6 +908,7 @@ int main(int argc, char *argv[]) {
     }
     pthread_join(read_id, NULL);
     taos_close(rInfo->taos);
+    free(rInfo);
   }
 
   taos_cleanup();

src/query/src/qParserImpl.c

@@ -279,7 +279,7 @@ tSQLExpr *tSqlExprCreate(tSQLExpr *pLeft, tSQLExpr *pRight, int32_t optrType) {
     pExpr->nSQLOptr = optrType;
     pExpr->pLeft = pLeft;
 
-    if (pRight == NULL) {
+    if (pLeft != NULL && pRight == NULL) {
       pRight = calloc(1, sizeof(tSQLExpr));
     }