diff --git a/src/query/src/qfill.c b/src/query/src/qfill.c
index 8c8a50a3d86abf4d27439286a7a6d0918720efd3..a8cd62ef981a8245671eede6e314dedc0d2cd84f 100644
--- a/src/query/src/qfill.c
+++ b/src/query/src/qfill.c
@@ -247,7 +247,7 @@ int taosDoLinearInterpolation(int32_t type, SPoint* point1, SPoint* point2, SPoi
 }
 
 static void setTagsValue(SFillInfo* pColInfo, tFilePage** data, char** pTags, int32_t start, int32_t num) {
-  for (int32_t j = 0, i = start; i < pColInfo->numOfCols + pColInfo->numOfTags; ++i, ++j) {
+  for (int32_t j = 0, i = start; i < pColInfo->numOfCols; ++i, ++j) {
     SFillColInfo* pCol = &pColInfo->pFillCol[i];
     
     char* val1 = elePtrAt(data[i]->data, pCol->col.bytes, num);
@@ -344,7 +344,7 @@ static void doInterpoResultImpl(SFillInfo* pFillInfo, tFilePage** data, int32_t*
       setTagsValue(pFillInfo, data, pTags, numOfValCols, *num);
   
     }
-  } else { /* default value interpolation */
+  } else { /* fill the default value */
     for (int32_t i = 1; i < numOfValCols; ++i) {
       SFillColInfo* pCol = &pFillInfo->pFillCol[i];