diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index cbb128045eb849d00b9b9b03ea0c9d04abd37de7..2f0bc3ecc8182008495b1dd02ff4042a51fd07f1 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -620,9 +620,13 @@ static void filterDataInDataBlock(STsdbQueryHandle* pQueryHandle, STableCheckInf
         if (pCol->info.type != TSDB_DATA_TYPE_BINARY && pCol->info.type != TSDB_DATA_TYPE_NCHAR) {
           memmove(pCol->pData, src->pData + bytes * start, bytes * pQueryHandle->realNumOfRows);
         } else { // handle the var-string
+          char* dst = pCol->pData;
+  
+          // todo refactor, only copy one-by-one
           for(int32_t k = start; k < pQueryHandle->realNumOfRows + start; ++k) {
             char* p = tdGetColDataOfRow(src, k);
-            memcpy(pCol->pData + k * bytes, p, varDataTLen(p));  // todo refactor
+            memcpy(dst, p, varDataTLen(p));
+            dst += varDataTLen(p);
           }
         }
         
diff --git a/tests/script/general/parser/lastrow_query.sim b/tests/script/general/parser/lastrow_query.sim
index a5e003fb651e69024326c58e5d8716d6509f28a2..e43cc1517398dd067bad7531d0960b3a459cde27 100644
--- a/tests/script/general/parser/lastrow_query.sim
+++ b/tests/script/general/parser/lastrow_query.sim
@@ -43,9 +43,11 @@ if $data07 != 1 then
   return -1
 endi
 if $data08 != BINARY then
+  print expect BINARY actual: $data08
   return -1
 endi
 if $data09 != NCHAR then
+  print expect NCHAR actual: $data09
   return -1
 endi