SQL选出相同记录和删除相同记录

选出相同记录的SQL语句是：
select * from tableName where id in (
select id from tableName group by id having count(*) > 1)

删除相同记录的SQL语句是：
delete from tableName where id in (
select id from tableName group by id having count(*) > 1)
注意，这样所有相同的记录都删除了，一条也不剩下。