diff --git a/src/query/src/qAggMain.c b/src/query/src/qAggMain.c
index d015b4cf11c34da66a8483e6ed43e0977b0dce27..c8c73e4cf397f57054001b63ee405eb2bf168b17 100644
--- a/src/query/src/qAggMain.c
+++ b/src/query/src/qAggMain.c
@@ -4710,7 +4710,7 @@ static void copySampleFuncRes(SQLFunctionCtx *pCtx, int32_t type) {
   TSKEY* pTimestamp = pCtx->ptsOutputBuf;
   char* pOutput = pCtx->pOutput;
   for (int32_t i = 0; i < pRes->numSampled; ++i) {
-    assignVal(pOutput, pRes->values + i*pCtx->inputBytes, pRes->colBytes, type);
+    assignVal(pOutput, pRes->values + i*pRes->colBytes, pRes->colBytes, type);
     *pTimestamp = *(pRes->timeStamps + i);
 
     pOutput += pCtx->outputBytes;