Question

我有一个名为“Calls”的表。表格的列组织为

CallCounter, AssignedEmpID, CompletedByEmpID
1            200            200
2            200            200
3            201            200
4            200            200
5            201            201
6            201            200
7            200            200
8            200            200
9            200            201
10           201            201
...

如何创建将返回以下数据的Select SQL查询。理想情况下，我想在1个查询中完成整个SQL查询。

Employee    # Calls Assigned    # Calls Completed
200         6                   7
201         4                   3

我尝试了以下查询

SELECT AssignedEmpID, COUNT(CallCounter) FROM CALLS
SELECT COUNT(*) FROM Calls

Answer 1

首先，您需要定义员工列表。如果您没有union表到employees，则可以使用子查询和join执行此操作。

然后你可以使用conditional aggregation：

select t.empid, 
    sum(case when t.empid = c.AssignedEmpID then 1 else 0 end) AssignedCount,
    sum(case when t.empid = c.CompletedByEmpID then 1 else 0 end) CompletedCount
from (select distinct AssignedEmpID as empid from calls 
      union select distinct CompletedByEmpID from calls) t
        join calls c on t.empid in (c.AssignedEmpID, c.CompletedByEmpID)
group by t.empid

Answer 2

我会使用union all和group by：

执行此操作

select EmpId, sum(assigned) as assigned, sum(completed) as completed
from ((select AssignedEmpID as EmpId, 1 as assigned, 0 as completed
       from calls
      ) union all
      (select CompletedByEmpID, 0, 1
       from calls
      )
     ) e
group by EmpId;

另一种方法是full outer join：

select coalesce(a.EmpId, c.EmpId),
       coalesce(assigned, 0) as assigned, 
       coalesce(completed, 0) as completed
from (select AssignedEmpID as EmpId, count(*) as assigned
      from calls
      group by AssignedEmpID
     ) a full outer join
     (select CompletedByEmpID as EmpId, count(*) as completed
      from calls
      group by CompletedByEmpID
     ) c
     on a.EmpId = c.EmpId;

如何为表中的每个用户选择Count

2 个答案: