fix(query): enable merge duplicated rows.

source/dnode/vnode/src/tsdb/tsdbRead.c

@@ -3426,8 +3426,8 @@ int32_t doMergeMemTableMultiRows(TSDBROW* pRow, uint64_t uid, SIterInfo* pIter,
     }
   }
 
-#if 0
-  // todo handle the data block merge
+  // start to merge duplicated rows
+  if (current.type == TSDBROW_ROW_FMT) {
     SRowMerger merge = {0};
 
     // get the correct schema for data in memory
@@ -3458,14 +3458,15 @@ int32_t doMergeMemTableMultiRows(TSDBROW* pRow, uint64_t uid, SIterInfo* pIter,
       return code;
     }
 
-  code = tsdbRowMergerGetRow(&merge, pTSRow);
+    code = tsdbRowMergerGetRow(&merge, &pResRow->pTSRow);
     if (code != TSDB_CODE_SUCCESS) {
       return code;
     }
 
+    pResRow->type = current.type;
     tsdbRowMergerClear(&merge);
     *freeTSRow = true;
-#endif
+  }
 
   return TSDB_CODE_SUCCESS;
 }