Postgresql语句以列方式表示重复的行

Question

我的数据如下：

Member_ID	Housing_ID	National_ID	Family_relation
1	1	3214565	Head
2	1	1234567	Wife
3	1	1223344	Sun
4	1	3224451	Sun
5	1	5432175	Daughter
1	2	1223344	Head
2	2	4321678	Wife
3	2	4356723	Sun
1	3	3214565	Head
2	3	1234557	Brother
1	4	7653432	Head
2	4	3224451	Grand daughter

如您所见，在不同的房屋中存在身份证件的重复：

1- the member 3 of house 1 with National ID 1223344 (sun) is (head) of house 2, 
2- the member 4 of house 1 with National ID 3224451 (sun) is (Grand daughter) of house 4

我必须指定所有重复的场景才能将其删除，我通过键入以下内容来识别重复：select National ID , count(*) from my table group by National ID having count(*)>1 并得到以下输出：

National ID	count
1223344	2
3224451	2

我懒得查询重复项，所以输出看起来像：

National ID	Housing ID 1	Relation	Housing ID 2	Relation
1223344	1	sun	2	Head
3224451	1	sun	4	Grand daughter

谢谢

Answer 1

对于 count(*) = 2 的 National_ID，以下查询应提供预期结果：

select National ID
     , array_agg(Housing_ID)[1] AS "Housing ID 1"
     , array_agg(Family_relation)[1] AS "Relation 1"
     , array_agg(Housing_ID)[2] AS "Housing ID 2"
     , array_agg(Family_relation)[2] AS "Relation 2"
  from my table 
 group by National_ID 
having count(*) = 2

Postgresql语句以列方式表示重复的行

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