Question

SQL查询语句,怎样查询重复数据

有表A, 中有字段id, name, memo
现在有很多id重复的数据,怎么把这些重复的都查出来?
group by? 请写出SQL语句, 谢谢

Answer 1

select id, name, memo
from A
where id in (select id from A group by id having count(1) >= 2)

Answer 2

select count(*),id from 表名 group by id having count(*)>1

Answer 3

select id,count(1) as num from table where num>1 group by id

Answer 4

select id,count(*) from A group by A.id havinig count(*)>1;

Answer 5

我们假如在goods表中id是唯一的，其中name可能会相同，现在要查出name存在重复的所有条目，sql可以这样写，可能理解不同，仅供参考
select id,name from goods WHERE name in ( SELECT name FROM goods GROUP BY name HAVING COUNT(name) > 1)