Question

jsp与数据库连接，分页查询为什么有重复的显示

第一页显示5条，第二页会重复显示第一页的后四条为什么？
select top 5 userName, userPass,userRole from loginUser where (userName not in (select top 0 userName from loginUser) and userRole='2')

上面为sql语句！

Answer 1

没有order by 语句，数据库的默认排序是不可靠的。

追问

那就是
select top 5 userName, userPass,userRole from loginUser where (userName not in (select top 0 userName from loginUser) and userRole='2') order by userName？这样么?还是不对，我试验了！>_<

追答

select top 5 userName, userPass,userRole from loginUser where userRole='2' and (userName not in (select top 0 userName from loginUser where userRole='2' order by userName)

Answer 2

使用group by 进行分组