计算个人之前与其他团队成员在当前团队之前的关系

Question

我想计算每个成员在组建团队之前与其他团队成员之前的关系数量。

我有以下表

TeamId \t UserId \t Date 
 
1 \t  100 \t 2/1/2017 
 
1 \t  101 \t 2/1/2017 
 
1 \t  102 \t 2/1/2017 
 
2 \t  100 \t 2//1/2016 
 
2 \t  105 2//1/2016 
 
3 \t  100 \t 2//1/2015 
 
3 \t  101 \t 2//1/2015 
 
3 \t  102 \t 2//1/2015 
 
3 \t  105 \t 2//1/2015 
 
3 \t  106 \t 2//1/2015 
 
4 \t  101 1/3/2015 
 
4 \t  102 \t 1/3/2015 
 
4 \t  105 1/3/2015 
 
4 \t  106 \t 1/3/2015

我想下表

TeamId \t number of previous collaborations 
 
1  \t 4 
 
2 \t   1 
 
3  \t 6 
 
4 \t   0

例如FO得到用户100与用户101曾经在队伍3中合作过，而用户102曾经在队伍3中合作过，因此用户101已经与用户102合作两次（一次在队伍3中，一次在队伍4中） = 1 + 1 = 2

所以以前的合作为这支球队的数量为4

我不知道怎么写的代码。任何帮助表示赞赏

SELECT [TeamId], 
 
COUNT(SELECT [Date] FROM [submissions] s1 
 
     WHERE s.[UserId] = [submissions].[UserId] 
 
     AND [Date]< [submissions].[Date] 
 
     ORDER BY [DateSubmitted] DESC) as Num_Collaborations 
 
    ) 
 
FROM [submissions]

Answer 1

这是一个具有挑战性的问题。你必须包括在查询相同的表4次：

select t1.TeamId, t1.UserId, t2.TeamId as OtherTeam, t3.UserId as Collaborator 
from @table t1, @table t2, @table t3, @table t4 
where t1.UserId = t2.UserId and 
     t2.TheDate < t1.TheDate and 
     t3.TeamId = t2.TeamId and 
     t4.TeamId = t1.TeamId and 
     t4.UserId = t3.UserId and 
     t4.UserId < t1.UserId 

http://rextester.com/LHZS40204

（那么你可以通过组和计数得到最终的结果）

Answer 2

你可以得到一个自加入所有用户的合作：

select s.userid, s2.userid as userid2, s.date, 
     row_number() over (order by (select null)) as c_id 
from submissions s join 
    submissions s2 
    on s2.teamid = s.teamid; 

让我们用这个作为一个子查询来回答你的问题。这个想法是将协作与提交相匹配 - 限制了两个用户在后面的日期在同一个团队。然后，您可以汇总：

with c as (
     select s.userid, s2.userid as userid2, s.date, 
      row_number() over (order by (select null)) as c_id 
     from submissions s join 
      submissions s2 
      on s2.teamid = s.teamid 
    ) 
select s1.teamid, count(distinct c_id) as num_previous_collaborations 
from c c join 
    submissions s1 
    on s1.userid = c.userid and 
     s1.date > c.date join -- they are later on a team 
    submissions s2 
    on s2.userid = c.userid2 and 
     s2.teamid = s1.teamid 
group by s1.teami;