diff --git a/src/client/src/tscFunctionImpl.c b/src/client/src/tscFunctionImpl.c
index 62ef1adfa4..be3dce9c0e 100644
--- a/src/client/src/tscFunctionImpl.c
+++ b/src/client/src/tscFunctionImpl.c
@@ -3191,7 +3191,7 @@ static void diff_function(SQLFunctionCtx *pCtx) {
     } else {                                                                                 \
       *(type *)(ctx)->aOutputBuf = *(type *)(d) - (*(type *)(&(ctx)->param[1].i64Key));      \
       *(type *)(&(ctx)->param[1].i64Key) = *(type *)(d);                                     \
-      *(int64_t *)(ctx)->ptsOutputBuf = *(int64_t *)((ctx)->ptsList[index]); \
+      *(int64_t *)(ctx)->ptsOutputBuf = (ctx)->ptsList[index];                               \
     }                                                                                        \
   } while (0);