目录

1. 不需要null值

2. 需要null值

没看懂留言 , 百度搜索半天基本上想要的很少

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1. 不需要null值

把 and条件放在最后

SELECT             ad.dept_id,             ad.dept_name,             au.id,             au.realname         FROM              user_post aup                  LEFT JOIN dept ad ON aup.dept_id = ad.dept_id     left join build_rec_user abru  on abru.order_id=ad.dept_id                     LEFT JOIN user au  ON au.id = abru.user_id         WHERE ad.company_id = 100   and abru.type_id = 0

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2. 需要null值

其实就是在 left join ... on 后面添加 and 条件 = ? 进行筛选 关联库条件

例子:left join build_rec_user abru
on abru.order_id=ad.dept_id and abru.type_id = 0

SELECT             ad.dept_id,             ad.dept_name,             au.id,             au.realname         FROM              user_post aup                  LEFT JOIN dept ad ON aup.dept_id = ad.dept_id     left join build_rec_user abru              on abru.order_id=ad.dept_id   and abru.type_id = 0                   LEFT JOIN user au  ON au.id = abru.user_id         WHERE ad.company_id = 100  

没看懂留言 , 百度搜索半天基本上想要的很少