Background
Database notes exist, but a concise SQL and indexing cheat sheet would improve final-stage review efficiency.
Suggested scope
- 索引失效场景
- 最左前缀原则
- 覆盖索引与回表
- Join / 子查询常见问法
- 事务与隔离级别高频题
Why it matters
This would complement the deeper notes with a high-signal review page.
Background
Database notes exist, but a concise SQL and indexing cheat sheet would improve final-stage review efficiency.
Suggested scope
Why it matters
This would complement the deeper notes with a high-signal review page.