求助sql 联合查询分组
SELECT userid,CONVERT(VARCHAR(10),checktime,120) AS 'date',MIN(checktime) AS 't1' FROM checkinout where (checktime>'2013-6-1 1:00:00' and checktime<'2013-6-30 23:50:00') GROUP BY CONVERT(VARCHAR(10),checktime,120),userid order by userid,'date'

这个查询用户每天最早的checktime，

SELECT userid,,CONVERT(VARCHAR(10),checktime,120) AS 'date',min(checktime) as t2 from checkinout where datename(hh,checktime)>12 and (checktime>'2013-6-1 1:00:00' and checktime<'2013-6-30 23:50:00') group by CONVERT(VARCHAR(10),checktime,120),userid order by userid

这个查询用户每天下午最早的checktime， 数据都在一个表，怎么把2个结果连接起来

[解决办法]

SELECT userid,CONVERT(VARCHAR(10),checktime,120) AS 'date',MIN(checktime) AS 't1' FROM checkinout where (checktime>'2013-6-1 1:00:00' and checktime<'2013-6-30 23:50:00') GROUP BY CONVERT(VARCHAR(10),checktime,120),userid order by userid,'date'

union all

SELECT userid,,CONVERT(VARCHAR(10),checktime,120) AS 'date',min(checktime) as t2 from checkinout where datename(hh,checktime)>12 and (checktime>'2013-6-1 1:00:00' and checktime<'2013-6-30 23:50:00') group by  CONVERT(VARCHAR(10),checktime,120),userid order by userid

SELECT userid,
       CONVERT(VARCHAR(10), checktime, 120) AS 'date',
       Min(checktime)                       AS 't1',
       NULL                                 't2'
FROM   checkinout
WHERE  ( checktime > '2013-6-1 1:00:00' 
 
         AND checktime < '2013-6-30 23:50:00' )
GROUP  BY CONVERT(VARCHAR(10), checktime, 120),
          userid
UNION
SELECT userid,
       CONVERT(VARCHAR(10), checktime, 120) AS 'date',
       NULL,
       Min(checktime)                       AS t2
FROM   checkinout
WHERE  Datename(hh, checktime) > 12
       AND ( checktime > '2013-6-1 1:00:00'
             AND checktime < '2013-6-30 23:50:00' )
GROUP  BY CONVERT(VARCHAR(10), checktime, 120),
          userid
ORDER  BY userid

--横向连接
SELECT a.userid, a.[date], a.t1, b.t2
FROM
(
SELECT  userid ,
CONVERT(VARCHAR(10), checktime, 120) AS [date] ,
MIN(checktime) AS [t1]
FROM    checkinout
WHERE   ( checktime > '2013-6-1 1:00:00'
  AND checktime < '2013-6-30 23:50:00' )
GROUP BY CONVERT(VARCHAR(10), checktime, 120) , userid
) M
LEFT JOIN
(
SELECT  userid ,
CONVERT(VARCHAR(10), checktime, 120) AS [date] ,
MIN(checktime) AS t2
FROM    checkinout
WHERE   DATENAME(hh, checktime) > 12
AND ( checktime > '2013-6-1 1:00:00'
  AND checktime < '2013-6-30 23:50:00' )
GROUP BY CONVERT(VARCHAR(10), checktime, 120) , userid
) N
ON m.Userid = n.Userid
AND m.[date] = n.[date]

--纵向连接
SELECT  orderfile = 1,
userid ,
        CONVERT(VARCHAR(10), checktime, 120) AS 'date' ,
        MIN(checktime) AS [t1] 
 
FROM    checkinout
WHERE   ( checktime > '2013-6-1 1:00:00'
          AND checktime < '2013-6-30 23:50:00'
        )
GROUP BY CONVERT(VARCHAR(10), checktime, 120) ,
        userid
UNION ALL
SELECT  orderfile = 2,
userid ,
        CONVERT(VARCHAR(10), checktime, 120) AS 'date' ,
        MIN(checktime) AS t2
FROM    checkinout
WHERE   DATENAME(hh, checktime) > 12
        AND ( checktime > '2013-6-1 1:00:00'
              AND checktime < '2013-6-30 23:50:00'
            )
GROUP BY CONVERT(VARCHAR(10), checktime, 120) ,
        userid
ORDER BY orderfile, userid, [date]