如何在多列中查找重复项?

How do I find duplicates across multiple columns?(如何在多列中查找重复项?)

问题描述

所以我想做类似下面这个sql代码的事情:

So I want to do something like this sql code below:

select s.id, s.name,s.city 
from stuff s
group by s.name having count(where city and name are identical) > 1

要产生以下内容，(但忽略只有名称或只有城市匹配的地方，它必须在两列上):

To produce the following, (but ignore where only name or only city match, it has to be on both columns):

id      name  city   
904834  jim   London  
904835  jim   London  
90145   Fred  Paris   
90132   Fred  Paris
90133   Fred  Paris

推荐答案

Duplicated id for pair name and city:

Duplicated id for pairs name and city:

select s.id, t.* 
from [stuff] s
join (
    select name, city, count(*) as qty
    from [stuff]
    group by name, city
    having count(*) > 1
) t on s.name = t.name and s.city = t.city

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