LeetCode Delete Duplicate Emails
Problem
Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id.
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+----+------------------+
| Id | Email |
+----+------------------+
| 1 | john@example.com |
| 2 | bob@example.com |
| 3 | john@example.com |
+----+------------------+
Id is the primary key column for this table.
For example, after running your query, the above Person table should have the following rows:
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+----+------------------+
| Id | Email |
+----+------------------+
| 1 | john@example.com |
| 2 | bob@example.com |
+----+------------------+
删除邮件重复的记录,保留Id最小的
MySQL
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DELETE p1 FROM Person p1, Person p2 WHERE p1.Email = p2.Email AND p1.Id > p2.Id;
分析
无
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