有这样一张表 t_kq
id    name      qdtime                   qttime            adddate
1    test3    2010-12-24 13:53                            2010-12-24
2    test3                          2010-12-24 14:53      2010-12-24
3    test3    2010-12-24 9:53                             2010-12-24
4    test3                          2010-12-24 17:53      2010-12-24
5    test3    2010-12-25 20:30                            2010-12-25
6    test3                          2010-12-26 8:30       2010-12-26

希望查询结果显示sql

同一天qdtime取最大值，qttime取最小值，如果当天没有qttime则显示第2天的qttime
使用 select name,max(qdtime),min(qttime),adddate from t_kq group by name,adddate
结果显示
name      qdtime                   qttime            adddate
test3    2010-12-24 13:53      2010-12-24 14:53      2010-12-24  
test3    2010-12-25 20:30         NULL               2010-12-25
test3    NULL                  2010-12-26 8:30       2010-12-26

如果想查询以下结果，sql语句应该怎么写。忘高人指点
 name      qdtime                   qttime            adddate
test3    2010-12-24 13:53      2010-12-24 14:53      2010-12-24  
test3    2010-12-25 20:30      2010-12-26 8:30       2010-12-26

小弟先谢谢了！

GO
--构造基础数据表
    if exists(select * from sysobjects where name = 't_kq' and xtype = 'u')
        drop table t_kq
GO
    create table t_kq(
    id int,
    name varchar(20),
    qdtime datetime,
    qttime datetime,
    adddate date)
   
Go
--为基础数据填充表结构
    insert into t_kq
    select 1, 'test1', '2010-12-24 13:53:00', null, '2010-12-24'
    union all
    select 2, 'test1', null, '2010-12-24 14:53:00', '2010-12-24'
    union all
    select 3, 'test1', '2010-12-24 9:53:00', null, '2010-12-24'
    union all
    select 4, 'test1', null, '2010-12-24 17:53:00', '2010-12-24'
    union all
    select 5, 'test1', '2010-12-25 20:30:00', null, '2010-12-25'
    union all
    select 6, 'test1', null, '2010-12-26 8:30:00', '2010-12-26'
   
GO

--查询实现方式
select a.name, a.qdtime, min(d.qttime)
    from t_kq a
    inner join t_kq d on a.adddate<=d.adddate and d.qttime is not null
    where not exists(select qdtime from t_kq b where a.adddate=b.adddate and a.qdtime<b.qdtime)
    and a.qdtime is not null
    group by a.name, a.qdtime

你先看看这个代码，有问题留言！

GO
--构造基础数据表
    if exists(select * from sysobjects where name = 't_kq' and xtype = 'u')
        drop table t_kq
GO
    create table t_kq(
    id int,
    name varchar(20),
    qdtime datetime,
    qttime datetime,
    adddate date)
   
Go
--为基础数据填充表结构
    insert into t_kq
    select 1, 'test1', '2010-12-24 13:53:00', null, '2010-12-24'
    union all
    select 2, 'test1', null, '2010-12-24 14:53:00', '2010-12-24'
    union all
    select 3, 'test1', '2010-12-24 9:53:00', null, '2010-12-24'
    union all
    select 4, 'test1', null, '2010-12-24 17:53:00', '2010-12-24'
    union all
    select 5, 'test1', '2010-12-25 20:30:00', null, '2010-12-25'
    union all
    select 6, 'test1', null, '2010-12-26 8:30:00', '2010-12-26'
   
GO

--查询实现方式
select a.name, a.qdtime, min(d.qttime) qttime,min(d.adddate) adddate
    from t_kq a
    inner join t_kq d on a.adddate<=d.adddate and d.qttime is not null
    where not exists(select qdtime from t_kq b where a.adddate=b.adddate and a.qdtime<b.qdtime)
    and a.qdtime is not null
    group by a.name, a.qdtime

test1    2010-12-24 13:53:00.000    2010-12-24 14:53:00.000    2010-12-24
test1    2010-12-25 20:30:00.000    2010-12-26 08:30:00.000    2010-12-26
上面忘记了AddDate字段，现在补上了并贴了结果。

谢谢，很好

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