Shulou(Shulou.com)06/01 Report--

There are two fields id and name in Zhang table to query all the data duplicated by name, which is now listed below:

Select * from xi a where (a.username) in (select username from xi group by username having count (*) > 1)

HAVING clause

The reason for adding the HAVING clause in SQL is that the WHERE keyword cannot be used with the aggregate function.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.