Question

美好的一天，

我有一个包含用户活动信息的表。

表格基本如下：

Eventdate,     UserId,       Activity
2013-09-09     SusanM        Support Call
2013-09-09     BrandonP      Meeting
2013-09-09     MumbaM        Administration
2013-09-16     SusanM        Support Call
2013-09-16     BrandonP      Meeting

所以你可以看到每个人都已经更新了9号工作，但是用户MumbaM还没有记录他的第16个参赛作品。如果我选择第16个MumbaM的日期，即使他在数据库中没有条目，是否可以在报告上显示？有没有办法根据以前的用户ID条目来修改SQL查询以包含Mumbam为16日。

所以我希望16日的报告显示如下：

2013-09-16     SusanM        Support Call
2013-09-16     BrandonP      Meeting
2013-09-16     MumbaM        no update yet

Answer 1

你可以试试这个：

SELECT t1.Eventdate, t1.UserId, t1.Activity
FROM YourTable t1
WHERE t1.Eventdate = '2013-09-16'

UNION

SELECT t1.Eventdate, t1.UserId, 'No update yet' as Activity
FROM YourTable t1
WHERE t1.userid not in (SELECT UserId FROM YourTable WHERE Eventdate = '2013-09-16')
    AND t1.Eventdate = 
        (SELECT TOP 1 t3.Eventdate FROM YourTable as t3 WHERE t3.UserID = t1.UserId)
GROUP BY t1.UserID, t1.Eventdate
ORDER BY Eventdate DESC

Answer 2

我认为你可以尝试这样的东西，但不是“还没有更新”，你会得到NULL;

SELECT t1.Eventdate, t1.UserId, t2.Activity
From Table t1
Left Outer Join Table t2
on t1.UserId = t2.UserId
Where Eventdate = '2013/09/16'

Answer 3

您可以使用解码或案例，而不是加入：

SELECT TRUNC (SYSDATE),
       userid,
       CASE TRUNC (eventdate)
          WHEN TRUNC (SYSDATE) THEN Activity
          ELSE 'no update yet'
       END
  FROM TABLE

Answer 4

假设您有两个表'Activity'和'User'，如下所示：

用户

Id, UserId 1 SusanM 2 BrandonP 3 MumbaM 4 SusanM 5 BrandonP

<强>活动

Eventdate, UserId, Activity 2013-09-09 SusanM Support Call 2013-09-09 BrandonP Meeting 2013-09-09 MumbaM Administration 2013-09-16 SusanM Support Call 2013-09-16 BrandonP Meeting

以下查询将为您提供所需的结果：

select u.UserId, NVL(a.Activity, 'no update yet') as Activity from user u left outer join activity a on a.UserId=u.UserId where a.Eventdate=sysdate

如何在数据库中尝试显示上周没有条目的用户

4 个答案: