从特定的Postgresql表中仅删除重复项

Question

我有一个包含重复项的表，我希望每个重复项只保留一行。

我可以使用SQL命令选择重复项：

SELECT DISTINCT ON (email, first_name, last_name) * from customer;

但是我想在先前的命令中使用DELETE。

此命令应该正常工作吗？

DELETE FROM customer WHERE customer.id NOT IN 
    (SELECT id FROM 
        (SELECT DISTINCT ON (email, first_name, last_name) * from customer));

是真的吗？

Answer 1

我想您有一个id字段。

delete from customer 
where id not in (
    select min(id)
    from customer
    group by email, first_name, last_name
)

子查询找到要保留的行的ID。 然后删除其他行

Answer 2

1. 我在ID中找不到您的(SELECT DISTINCT ON (email, first_name, last_name) * from customer));
2. distinct on仅返回不可预测的复制数据的第一行