关于sql 数据清理的问题
现在假设有一张学生住宿信息表，sql字段有 id（不是学号），房号，上次时间，本次时间，住宿名单1，住宿名单2，住宿名单3，住宿名单4， 要怎么通过这些字段找出是否有同名的学生。

[解决办法]

SQL code

with cte as (select *, row_number() over( order by getdate()) as id from (select 住宿名单1 as col from tbunion allselect 住宿名单2 from tbunion allselect 住宿名单3 from tbunion allselect 住宿名单4 from tb) as t )select * from cte as a where exists (   select * from cte as b       where a.col = b.col and             a.id <> b.id)