Skip to content

Latest commit

 

History

History
50 lines (39 loc) · 1.1 KB

File metadata and controls

50 lines (39 loc) · 1.1 KB

196. Delete Duplicate Emails

Description

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  |
+----+------------------+

Note:

Your output is the whole Person table after executing your sql. Use delete statement.

Solution

  • mysql
/*
 Success Detail:
 Runtime: 1451 ms, faster than 56.85% of MySQL online submissions for Delete Duplicate Emails.
 Memory Usage: 0 MB, less than 100% of MySQL online submissions for Delete Duplicate Emails.
 */
DELETE p1
FROM Person p1,
     Person p2
WHERE p1.Email = p2.Email
  AND p1.Id > p2.Id