sql語句 查詢重複的項

查詢List中a重複的項

1、select a from List group by a having count(*) > 1

2、select * from list where a in (select a from List group by a having count(*) > 1)

3、select * from List where (select count(*) from List s where s.a = List.a) > 1

篩選分組之後的結果，使用having