Skip to content

Latest commit

 

History

History
73 lines (32 loc) · 1.23 KB

File metadata and controls

73 lines (32 loc) · 1.23 KB

中文文档

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.

Solutions

SQL

delete from Person where Id not in (select min(Id) from (select * from Person) as p group by p.Email)