pingcap/tidb

Error should be thrown when there's ASC/DESC with GROUP BY clause

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#10,522 创建于 2019年5月17日

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help wantedpriority/P4sig/plannertype/feature-request

描述

Bug Report

Please answer these questions before submitting your issue. Thanks!

  1. What did you do? If possible, provide a recipe for reproducing the error.
CREATE TABLE t1 (id INTEGER, sex CHAR(1));
SELECT sex, AVG(id), ROW_NUMBER() OVER w FROM t1
GROUP BY sex ASC
WINDOW w AS () ORDER BY sex DESC;
  1. What did you expect to see?

Error ASC or DESC with GROUP BY isn't allowed with window functions; put ASC or DESC in ORDER BY is thrown.

  1. What did you see instead?

Execute successfully with no warning.

  1. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

贡献者指南

技术栈
gosql
领域
backenddatabase
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
half day
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
SQL GROUP BY and window functionsGo language basics
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
50
研究方向
The issue is that TiDB should throw an error when ASC/DESC is used with GROUP BY in the presence of window functions. The fix requires locating where the SQL query is parsed and validated. The parser or planner likely accepts this syntax erroneously. Examine the parser files (e.g., `parser/ast/select.go`) and the planner rules (e.g., `planner/core/rule aggregation push down.go`) to add a check that rejects such queries. Look at similar error messages in the codebase for reference.