[td-4973]<fix>:fix the conversion bug in outer query when handling the data of nchar type.

src/client/inc/tscUtil.h

@@ -217,7 +217,7 @@ void tscColumnListDestroy(SArray* pColList);
 void tscColumnListCopy(SArray* dst, const SArray* src, uint64_t tableUid);
 void tscColumnListCopyAll(SArray* dst, const SArray* src);
 
-void convertQueryResult(SSqlRes* pRes, SQueryInfo* pQueryInfo, uint64_t objId);
+void convertQueryResult(SSqlRes* pRes, SQueryInfo* pQueryInfo, uint64_t objId, bool convertNchar);
 
 void tscDequoteAndTrimToken(SStrToken* pToken);
 int32_t tscValidateName(SStrToken* pToken);

src/client/inc/tsclient.h

@@ -319,7 +319,7 @@ void    tscRestoreFuncForSTableQuery(SQueryInfo *pQueryInfo);
 
 int32_t tscCreateResPointerInfo(SSqlRes *pRes, SQueryInfo *pQueryInfo);
 void tscSetResRawPtr(SSqlRes* pRes, SQueryInfo* pQueryInfo);
-void tscSetResRawPtrRv(SSqlRes* pRes, SQueryInfo* pQueryInfo, SSDataBlock* pBlock);
+void tscSetResRawPtrRv(SSqlRes* pRes, SQueryInfo* pQueryInfo, SSDataBlock* pBlock, bool convertNchar);
 
 void handleDownstreamOperator(SSqlObj** pSqlList, int32_t numOfUpstream, SQueryInfo* px, SSqlObj* pParent);
 void destroyTableNameList(SInsertStatementParam* pInsertParam);

src/client/src/tscServer.c

@@ -1703,7 +1703,7 @@ int tscProcessRetrieveGlobalMergeRsp(SSqlObj *pSql) {
 
   uint64_t localQueryId = pSql->self;
   qTableQuery(pQueryInfo->pQInfo, &localQueryId);
-  convertQueryResult(pRes, pQueryInfo, pSql->self);
+  convertQueryResult(pRes, pQueryInfo, pSql->self, true);
 
   code = pRes->code;
   if (pRes->code == TSDB_CODE_SUCCESS) {

src/client/src/tscUtil.c

@@ -645,7 +645,7 @@ void tscSetResRawPtr(SSqlRes* pRes, SQueryInfo* pQueryInfo) {
   }
 }
 
-void tscSetResRawPtrRv(SSqlRes* pRes, SQueryInfo* pQueryInfo, SSDataBlock* pBlock) {
+void tscSetResRawPtrRv(SSqlRes* pRes, SQueryInfo* pQueryInfo, SSDataBlock* pBlock, bool convertNchar) {
   assert(pRes->numOfCols > 0);
 
   for (int32_t i = 0; i < pQueryInfo->fieldsInfo.numOfOutput; ++i) {
@@ -678,7 +678,7 @@ void tscSetResRawPtrRv(SSqlRes* pRes, SQueryInfo* pQueryInfo, SSDataBlock* pBloc
         }
       }
 
-    } else if (pInfo->field.type == TSDB_DATA_TYPE_NCHAR) {
+    } else if (convertNchar && pInfo->field.type == TSDB_DATA_TYPE_NCHAR) {
       // convert unicode to native code in a temporary buffer extra one byte for terminated symbol
       pRes->buffer[i] = realloc(pRes->buffer[i], pInfo->field.bytes * pRes->numOfRows);
 
@@ -1072,14 +1072,14 @@ SOperatorInfo* createJoinOperatorInfo(SOperatorInfo** pUpstream, int32_t numOfUp
   return pOperator;
 }
 
-void convertQueryResult(SSqlRes* pRes, SQueryInfo* pQueryInfo, uint64_t objId) {
+void convertQueryResult(SSqlRes* pRes, SQueryInfo* pQueryInfo, uint64_t objId, bool convertNchar) {
   // set the correct result
   SSDataBlock* p = pQueryInfo->pQInfo->runtimeEnv.outputBuf;
   pRes->numOfRows = (p != NULL)? p->info.rows: 0;
 
   if (pRes->code == TSDB_CODE_SUCCESS && pRes->numOfRows > 0) {
     tscCreateResPointerInfo(pRes, pQueryInfo);
-    tscSetResRawPtrRv(pRes, pQueryInfo, p);
+    tscSetResRawPtrRv(pRes, pQueryInfo, p, convertNchar);
   }
 
   tscDebug("0x%"PRIx64" retrieve result in pRes, numOfRows:%d", objId, pRes->numOfRows);
@@ -1199,7 +1199,7 @@ void handleDownstreamOperator(SSqlObj** pSqlObjList, int32_t numOfUpstream, SQue
 
   uint64_t qId = pSql->self;
   qTableQuery(px->pQInfo, &qId);
-  convertQueryResult(pOutput, px, pSql->self);
+  convertQueryResult(pOutput, px, pSql->self, false);
 }
 
 static void tscDestroyResPointerInfo(SSqlRes* pRes) {

src/query/inc/qTableMeta.h

@@ -118,7 +118,6 @@ typedef struct SQueryInfo {
   int64_t          vgroupLimit;    // table limit in case of super table projection query + global order + limit
 
   int32_t          udColumnId;    // current user-defined constant output field column id, monotonically decreases from TSDB_UD_COLUMN_INDEX
-  int16_t          resColumnId;   // result column id
   bool             distinctTag;   // distinct tag or not
   int32_t          round;         // 0/1/....
   int32_t          bufLen;