[6046]<fix> fix ts always in first output index using derivative function

src/client/src/tscSQLParser.c

@@ -2594,13 +2594,12 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
 
       // set the first column ts for diff query
       if (functionId == TSDB_FUNC_DIFF || functionId == TSDB_FUNC_DERIVATIVE) {
-        colIndex += 1;
         SColumnIndex indexTS = {.tableIndex = index.tableIndex, .columnIndex = 0};
         SExprInfo*   pExpr = tscExprAppend(pQueryInfo, TSDB_FUNC_TS_DUMMY, &indexTS, TSDB_DATA_TYPE_TIMESTAMP,
                                          TSDB_KEYSIZE, getNewResColId(pCmd), TSDB_KEYSIZE, false);
 
         SColumnList ids = createColumnList(1, 0, 0);
-        insertResultField(pQueryInfo, 0, &ids, TSDB_KEYSIZE, TSDB_DATA_TYPE_TIMESTAMP, aAggs[TSDB_FUNC_TS_DUMMY].name, pExpr);
+        insertResultField(pQueryInfo, colIndex, &ids, TSDB_KEYSIZE, TSDB_DATA_TYPE_TIMESTAMP, aAggs[TSDB_FUNC_TS_DUMMY].name, pExpr);
       }
 
       SExprInfo* pExpr = tscExprAppend(pQueryInfo, functionId, &index, resultType, resultSize, getNewResColId(pCmd), intermediateResSize, false);