Question

我有2个常规表“任务”和“员工”和一个联结表EmployeeTasks简化它们看起来像这样

任务

的TaskID
专案编号
持续时间

员工

雇员
EmployeeName

EmployeeTasks

雇员
的TaskID

我正在尝试找到一个基于公共项目ID的tsql查询，它会提供每个员工花费的总时间和完成的任务数量的摘要。与此类似：

"Employee" | "Number of Tasks" | "Time Spent"
----------------------------------------
John       |        5          |  123
Sam        |        4          |   72

Answer 1

SELECT E.EmployeeName, COUNT(T.TaskID) AS [Number of Tasks], SUM(T.Duration) as [Time Spent]
FROM Employee E, EmployeeTasks ET, Tasks T
WHERE ET.EmployeeID = E.EmployeeID AND ET.TaskID = T.TaskID
GROUP BY E.EmployeeName

Answer 2

试试这个：

 Select EmployeeName, 
      Count(et.TaskId) NumTasks,
      Sum(T.Duration) TimeSpent
  From Employees E
     Left Join (EmployeeTasks eT Join Tasks T 
                   On T.TaskId = eT.TaskId)
        On eT.EmployeeId = E.EmployeeId 
  Where ProjectId = @ProjectId
  Group By EmployeeName

这将为所有员工 - 项目组合

  Select EmployeeName, ProjectId, 
      Count(et.TaskId) NumTasks,
      Sum(T.Duration) TimeSpent
  From Employees E
     Left Join (EmployeeTasks eT Join Tasks T 
                   On T.TaskId = eT.TaskId)
        On eT.EmployeeId = E.EmployeeId 
  Group By EmployeeName, ProjectId

Answer 3

请注意，如果您需要为没有任务的员工显示时间，则会有所不同。

SELECT Count(TaskID) as NumOfTasks, Sum(Duration) as TimeSpent
FROM Employee 
INNER JOIN EmployeeTasks on Employee.EmployeeID = Tasks.EmployeeID
INNER JOIN Tasks on EmployeeTasks.TaskID = Tasks.TaskID
WHERE ProjectID = @ProjectID
GROUP BY EmployeeID

如果您想要员工姓名，请将其作为子选择加入

SELECT EmployeeName, NumOfTasks, TimeSpent
FROM Employees 
INNER JOIN (insert select here) TaskSummary on Employees.EmployeeID = TaskSummary.EmployeeID

SQL通过联结表从另一个表中选择总和作为列

3 个答案: