Leetcode Original Quote:
Write a SQL query to delete all duplicate e-mail entries in a table named Person
, keeping unique emails based on its smallest Id.
+----+------------------+| Id | Email |+----+------------------+| 1 | [Email protected] | | 2 | [Email protected] | | 3 | [email protected] |+----+------------------+id is the primary key, column for this table.
For example, after running your query, the above Person
table should has the following rows:
+----+------------------+| Id | Email |+----+------------------+| 1 | [Email protected] | | 2 | [email protected] | +----+------------------+
My SQL statement:
DELETE from the person WHERE the ID is not in (the Select ID from (select MIN (ID) as ID from the person GROUP by email) as a);
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Leetcode Database SQL Delete Duplicate Emails