大表 JOIN 卡死说到底就三个原因：数据量没控制住、索引没跟上、执行顺序瞎搞。紧急的时候先止血控制数据量加索引，平时老老实实按规范写 SQL，架构上该拆就拆别心疼。 说出来你可能不信，去年双十一前一周，我们组的后端小哥差点提离职。 原因是他在 ...

ROW_NUMBER() OVER (ORDER BY salary DESC) as row_num, RANK() OVER (ORDER BY salary DESC) as rank_num, DENSE_RANK() OVER (ORDER BY salary DESC) as dense_rank_num LAG(total_amount, 1) OVER (PARTITION BY ...