modify unique logic, add error tips & fix order by logic

src/client/src/tscSQLParser.c

@@ -3146,7 +3146,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
       }
 
       // 2. valid the column type
-      if (functionId != TSDB_FUNC_SAMPLE && !IS_NUMERIC_TYPE(pSchema->type)) {
+      if (functionId != TSDB_FUNC_SAMPLE && functionId != TSDB_FUNC_UNIQUE && !IS_NUMERIC_TYPE(pSchema->type)) {
         return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg1);
       }
 

src/tsdb/src/tsdbRead.c

@@ -1749,6 +1749,7 @@ static int32_t doCopyRowsFromFileBlock(STsdbQueryHandle* pQueryHandle, int32_t c
     } else {
       pData = (char*)pColInfo->pData + (capacity - numOfRows - num) * pColInfo->info.bytes;
     }
+    memset(pData, 0, pColInfo->info.bytes);
 
     if (!isAllRowsNull(src) && pColInfo->info.colId == src->colId) {
       if (pColInfo->info.type != TSDB_DATA_TYPE_BINARY && pColInfo->info.type != TSDB_DATA_TYPE_NCHAR) {
@@ -1788,6 +1789,7 @@ static int32_t doCopyRowsFromFileBlock(STsdbQueryHandle* pQueryHandle, int32_t c
     } else {
       pData = (char*)pColInfo->pData + (capacity - numOfRows - num) * pColInfo->info.bytes;
     }
+    memset(pData, 0, pColInfo->info.bytes);
 
     if (pColInfo->info.type == TSDB_DATA_TYPE_BINARY || pColInfo->info.type == TSDB_DATA_TYPE_NCHAR) {
       char* dst = pData;