假設有表test

mysql> select * from test; +----+------+------+ | id | name | sex | +----+------+------+ | 1 | a | f | | 2 | b | f | | 3 | a | e | | 4 | b | e | | 5 | c | e | | 6 | d | e | +----+------+------+ 6 rows in set (0.00 sec)

?

現在要找出name列有重復的數據

mysql> select name from test group by name having count(name)>1; +------+ | name | +------+ | a | | b | +------+ 2 rows in set (0.00 sec)

?

如果還要求顯示name外其他數據

mysql> select * from test where name in (select name from test group by name having count(name)>1); +----+------+------+ | id | name | sex | +----+------+------+ | 1 | a | f | | 2 | b | f | | 3 | a | e | | 4 | b | e | +----+------+------+ 4 rows in set (0.00 sec)

?

或者要求顯示重復次數

mysql> select count(name) as 'number',name from test group by name having count(name)>1; +--------+------+ | number | name | +--------+------+ | 2 | a | | 2 | b | +--------+------+ 2 rows in set (0.00 sec)

?

或者要求顯示重復數據中id最小的那一個

mysql> select min(id),name from test group by name having count(name)>1; +---------+------+ | min(id) | name | +---------+------+ | 1 | a | | 2 | b | +---------+------+ 2 rows in set (0.00 sec)

?

轉載于:https://www.cnblogs.com/drizzlewithwind/p/6523436.html

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