leetcode数据库sql之Delete Duplicate Emails
leetcode原文引用:
Write a SQL query to delete all duplicate email entries in a table named Person
,
keeping only unique emails based on its smallest Id.
+----+------------------+
| 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:
+----+------------------+
| Id | Email |
+----+------------------+
| 1 | john@example.com |
| 2 | bob@example.com |
+----+------------------+
我的sql语句:
DELETE FROM Person WHERE id NOT IN (SELECT id FROM (SELECT MIN(id) AS id FROM Person GROUP BY email) AS a);