Question

我正在寻找一种删除表格中所有重复记录的方法。我有一个查询，但它不起作用：

delete from lista
where id in
(
    select id
    from lista
    group by tytul_pl
    having count(tytul_pl) > 1
);

服务器响应：

错误代码：1093。您无法为更新指定目标表'lista' FROM子句

此查询：

select id
from lista
group by tytul_pl
having count(tytul_pl) > 1

运作良好。

错误在哪里？

Answer 1

这样可以保留一条记录并删除所有其他副本：

DELETE t1 
FROM lista t1
JOIN lista t2 
 ON t1.id > t2.id 
AND t1.tytul_pl = t2.tytul_pl

Answer 2

我认为你想要的是这个

DELETE lista FROM lista 
LEFT OUTER JOIN (
      SELECT MIN(ID) AS minID 
      FROM lista 
      GROUP BY tytul_pl) AS keepRowTable ON lista.ID = keepRowTable.minID
WHERE keepRowTable.minID IS NULL

你可以try it out here

如何删除表格中的所有重复记录？

2 个答案: