Question

HI 我正在寻找一些帮助，我似乎无法理解自己如何加入工作。我有这个sql代码

select Persno'Name',convert(char(20), A_Date , 13)'Logins',acode 
from atrail as LOGIN 
where acode = 'LOGIN' OR acode = 'LOGOUT'
order by a_date desc

生成用户名列表以及登录和注销时。我想要实现的目标是在他们登录日期的日期旁边找到带有LOGOUT日期的花药列，以便在登录和退出时更容易看到。

由于

安迪

Answer 1

这应该这样做：

select      LOGIN.Persno  AS Name,
            LOGIN.a_date  AS login_date,    --//convert here as you like
            LOGOUT.a_date AS logout_date    --//convert here as you like

from        atrail as LOGIN

left join   atrail as LOGOUT
        ON  LOGOUT.Persno= LOGIN.Persno
        AND LOGOUT.acode = 'LOGOUT'

        AND LOGOUT.A_Date= (SELECT  TOP 1 x.A_Date
                            FROM    atrail x
                            WHERE   x.Persno = LOGIN.Persno
                                AND x.A_Date >= LOGIN.A_Date
                                AND x.acode = 'LOGOUT'
                            ORDER BY x.A_Date)
where       LOGIN.acode = 'LOGIN' 
order by    LOGIN.a_date desc

将以以下格式生成结果：

Name        login_date  logout_date
----------- ----------- -----------
pippo       2008-01-01  2008-01-03

Answer 2

这可能是实现它的另一种方式：

SELECT Name, [LOGIN] as login_date, [LOGOUT] as logout_date
FROM
(
    SELECT Persno Name,convert(char(20), A_Date , 13) Logins, acode
    FROM atrail 
    WHERE acode = 'LOGIN' OR acode = 'LOGOUT'
    ORDER BY a_date DESC
) AS login_table
PIVOT
(
    MAX(Logins) FOR acode IN ([LOGIN],[LOGOUT])
) AS pvt_table
ORDER BY login_date DESC

这是考虑到每个登录日期都有一个注销日期，每个人只有一个登录和一个注销行。

SQL SERVER 2005 Self连接输出

2 个答案: