Sqlalchemy 如何实现 case + subquery 嵌套 subquery - V2EX
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wuwukai007
V2EX    Python

Sqlalchemy 如何实现 case + subquery 嵌套 subquery

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  •   wuwukai007 2022-09-08 15:47:53 +08:00 2020 次点击
    这是一个创建于 1137 天前的主题,其中的信息可能已经有所发展或是发生改变。
    select case when user.id > 10000 then (select true_flag from score where created_time = ( select max(created_time) from score where user.id = score.user_id )) when user.id <= 10000 then (select true_flag from score_bak where created_time = ( select max(created_time) from score_bak where user.id = score_bak.user_id ) ) end true_flag from user; 
    • 使用 case 函数 最后会变成 select true_flag from user,score 把两个表连表了
    第 1 条附言    2022-09-08 17:00:09 +08:00

    真的瑞了,投降了,使用原生sql

    from sqlalchemy import text,select,column sql = text(sql) sql = sql.columns(column('true_flag')) subquery = select(sql.selected_columns.true_flag).select_from(sql.subquery()) 
    3 条回复    2022-09-09 09:58:16 +08:00
    xhzhang
        1
    xhzhang  
       2022-09-08 20:56:37 +08:00
    这个你可以把 case 语句放到 where 的 join 条件中,用 user join 两张表,添加不同的 join 条件,select 语句就按照你现在的逻辑取数就可以
    xhzhang
        2
    xhzhang  
       2022-09-08 20:58:48 +08:00
    select xxx from user join score on user.id = score.user_id and user.id > 10000 join score_bak on user.id = score.user_id and user.id <= 10000
    joApioVVx4M4X6Rf
        3
    joApioVVx4M4X6Rf  
       2022-09-09 09:58:16 +08:00
    试了一下好像还真是和楼主说的会变成连表
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