fix(query): copy null value.

source/common/src/tdatablock.c

@@ -1329,10 +1329,6 @@ SSDataBlock* createOneDataBlock(const SSDataBlock* pDataBlock, bool copyData) {
     for (int32_t i = 0; i < numOfCols; ++i) {
       SColumnInfoData* pDst = taosArrayGet(pBlock->pDataBlock, i);
       SColumnInfoData* pSrc = taosArrayGet(pDataBlock->pDataBlock, i);
-      if (pSrc->pData == NULL) {
-        continue;
-      }
-
       colDataAssign(pDst, pSrc, pDataBlock->info.rows, &pDataBlock->info);
     }
 

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

@@ -182,6 +182,7 @@ static int32_t setColumnIdSlotList(STsdbReader* pReader, SSDataBlock* pBlock) {
 
     if (IS_VAR_DATA_TYPE(pCol->info.type)) {
       pSupInfo->buildBuf[i] = taosMemoryMalloc(pCol->info.bytes);
+      tsdbInfo("-------------------%d\n", pCol->info.bytes);
     }
   }
 
@@ -674,6 +675,7 @@ static void doCopyColVal(SColumnInfoData* pColInfoData, int32_t rowIndex, int32_
       colDataAppendNULL(pColInfoData, rowIndex);
     } else {
       varDataSetLen(pSup->buildBuf[colIndex], pColVal->value.nData);
+      ASSERT(pColVal->value.nData <= pColInfoData->info.bytes);
       memcpy(varDataVal(pSup->buildBuf[colIndex]), pColVal->value.pData, pColVal->value.nData);
       colDataAppend(pColInfoData, rowIndex, pSup->buildBuf[colIndex], false);
     }