从 sql union 中删除重复项 [英] remove duplicates from sql union

问题描述

我正在使用联合(正确或错误)对我拥有的几个表执行一些基本的 sql

I'm doing some basic sql on a few tables I have, using a union(rightly or wrongly)

但我需要删除重复项.有什么想法吗?

but I need remove the duplicates. Any ideas?

select * from calls
left join users a on calls.assigned_to= a.user_id
where a.dept = 4 
union
select * from calls
left join users r on calls.requestor_id= r.user_id
where r.dept = 4

推荐答案

Union 将删除重复项.Union All 没有.

Union will remove duplicates. Union All does not.

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