180608_find_duplicate

作者: 郑磊_4135 | 来源:发表于2018-06-08 16:15 被阅读0次

Write a SQL query to find all duplicate emails in a table named Person.

Id Email
1 a@b.com
2 c@d.com
3 a@b.com

For example, your query should return the following for the above table:

Email
a@b.com
SELECT DISTINCT p1.Email
FROM Person p1, Person p2
WHERE p1.Email = p2.Email 
    AND p1.Id > p2.Id

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