Question

好吧，所以我有这个查询，几乎拉了我在数据库中得到的所有信息

Select 
p.ProjectName,
s.siteid,
c.PaperID,
m.MemberFirstName,
m.MemberLastName,
m.MemberDOB,
m.MemberID
From Sites s, Papers c, Members m, Projects p
Where s.SiteID=c.SiteID
and c.MemberID=m.MemberID
and s.ProjectID=p.ProjectID
order by ProjectName, MemberFirstName, MemberLastName

但是，我只是想查看我的查询，只显示会员进入多个网站时的多个实例

目前我的结果看起来像下面的输出 - 所以在这种特殊情况下，我想保留John Doe的结果，因为他出现在多个站点中（他的MemberID证明他是一样的John Doe并不是一个不同的John Doe，但我不想保留Jane Doe的结果，因为她只在一个网站上出现一次。

ProjectName | SiteID | PaperId |  MemberFirstName | MemberLastName | MemberDOB  | MemberID
-------------------------------------------------------------------------------------------
Project 1   | 123456 | 123     | Jane             | Doe            | 1991-01-01 | 12345
-------------------------------------------------------------------------------------------
Project 1   | 789012 | 321     | John             | Doe            | 1991-02-02 | 54321
-------------------------------------------------------------------------------------------  
Project 1   | 345678 | 456     | John             | Doe            | 1991-02-02 | 54321

Answer 1

您想要的是GROUP BY和HAVING。请注意，您无法选择相同的数据，因为每人会有多个SiteID。

这样的事情：

Select 
  m.MemberFirstName,
  m.MemberLastName,
  m.MemberDOB,
  m.MemberID
From Sites s, Papers c, Members m, Projects p
Where s.SiteID = c.SiteID
  and c.MemberID = m.MemberID
  and s.ProjectID = p.ProjectID
order by ProjectName, MemberFirstName, MemberLastName
GROUP BY 
  m.MemberFirstName,
  m.MemberLastName,
  m.MemberDOB,
  m.MemberID
HAVING COUNT(*) > 1

Answer 2

或者，如果SiteID很重要，您可以执行以下操作：

SELECT
ProjectName,
siteid,
PaperID,
MemberFirstName,
MemberLastName,
MemberDOB,
MemberID
FROM (
    Select 
    p.ProjectName,
    s.siteid,
    c.PaperID,
    m.MemberFirstName,
    m.MemberLastName,
    m.MemberDOB,
    m.MemberID,
    COUNT(1) OVER ( PARTITION BY m.MemberID ) AS CNT
    From Sites s, Papers c, Members m, Projects p
    Where s.SiteID=c.SiteID
    and c.MemberID=m.MemberID
    and s.ProjectID=p.ProjectID
    ) A
WHERE CNT > 1
order by ProjectName, MemberFirstName, MemberLastName

仅显示多个实例

2 个答案: