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);转载于:https://www.cnblogs.com/iamconan/p/7383575.html
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