我没有看到任何JOIN方法，它在复制方面有很多用途。

这种方法会给您带来实际的双倍结果。

SELECT t1.* FROM my_table as t1 
LEFT JOIN my_table as t2 
ON t1.name=t2.name and t1.id!=t2.id 
WHERE t2.id IS NOT NULL 
ORDER BY t1.name

如果你想删除重复使用DISTINCT

否则使用这个查询:

SELECT users.*，COUNT(user_ID) as user FROM users GROUP BY user_name有用户>

Select column_name, column_name1,column_name2, count(1) as temp from table_name group by column_name having temp > 1

假设您的表名为TableABC，您想要的列是Col, T1的主键是key。

SELECT a.Key, b.Key, a.Col 
FROM TableABC a, TableABC b
WHERE a.Col = b.Col 
AND a.Key <> b.Key

与上面的答案相比，这种方法的优点是它给出了Key。

为了获得所有包含复制的数据，我使用了以下方法:

SELECT * FROM TableName INNER JOIN(
  SELECT DupliactedData FROM TableName GROUP BY DupliactedData HAVING COUNT(DupliactedData) > 1 order by DupliactedData)
  temp ON TableName.DupliactedData = temp.DupliactedData;

TableName =您正在使用的表。

DupliactedData =您正在寻找的重复数据。

SELECT DISTINCT a.email FROM `users` a LEFT JOIN `users` b ON a.email = b.email WHERE a.id != b.id;