SQL查询：如何从给定的SQL查询中获取所有员工

Question

我有以下查询，我希望所有员工都出现在表中......如何做到这一点？

这是我的表：

SELECT E.EmployeeId --assuming ID is the PK of Employee (E) 
    , tb1.monthDate 
    , ISNULL(present, 0) as present 
    , ISNULL(expected, 0) as expected 
    , ISNULL(late, 0) as late 
FROM (SELECT distinct EmployeeId 
     FROM tblAttendanceDetails) E 
LEFT JOIN (SELECT EmployeeId as id,count(Logintime) as present, month(Logintime) as monthDate 
      FROM tblAttendanceDetails 
      WHERE cast(Logintime as time)< cast('09:20' as time) 
      GROUP BY EmployeeId,month(Logintime)) as tb1 
    on E.EmployeeId = tb1.id 
LEFT JOIN (SELECT EmployeeId,count(Logintime) as late, month(Logintime) as monthDate2 
      FROM tblAttendanceDetails 
      WHERE cast(Logintime as time)> cast('09:30' as time) 
      GROUP BY EmployeeId, month(Logintime)) as tb2 
    on E.EmployeeId=tb2.EmployeeId 
and tb1.monthDate=tb2.monthDate2 
LEFT JOIN (SELECT EmployeeId,count(Logintime) as expected,month(Logintime) as monthDate3 
      FROM tblAttendanceDetails 
      WHERE cast(Logintime as time) between cast('09:20' as time) and cast('09:30' as time) 
      GROUP BY EmployeeId,month(Logintime)) as tb3 
    on E.EmployeeId=tb3.EmployeeId 
and tb1.monthDate=tb3.monthDate3 

这是我的查询结果：

Answer 1

我设想是这样的......这样的滤波的子查询完成对员工的所有记录没有影响。

SELECT E.id --assuming ID is the PK of Employee (E) 
    , tb1.monthDate 
    , coalesce(present, 0) as present 
    , coalesce(expected, 0) as expected 
    , coalesce(late, 0) as late 
FROM Employee E 
LEFT JOIN (SELECT EmployeeId as id,count(Logintime) as present, month(Logintime) as monthDate 
      FROM tblAttendanceDetails 
      WHERE cast(Logintime as time)< cast('09:20' as time) 
      GROUP BY EmployeeId,month(Logintime)) as tb1 
    on E.ID = tb1.ID 
LEFT JOIN (SELECT EmployeeId,count(Logintime) as late, month(Logintime) as monthDate2 
      FROM tblAttendanceDetails 
      WHERE cast(Logintime as time)> cast('09:30' as time) 
      GROUP BY EmployeeId, month(Logintime)) as tb2 
    on E.id=tb2.EmployeeId 
and tb1.monthDate=tb2.monthDate2 
LEFT JOIN (SELECT EmployeeId,count(Logintime) as expected,month(Logintime) as monthDate3 
      FROM tblAttendanceDetails 
      WHERE cast(Logintime as time) between cast('09:20' as time) and cast('09:30' as time) 
      GROUP BY EmployeeId,month(Logintime)) as tb3 
    on E.id=tb3.EmployeeId 
and tb1.monthDate=tb3.monthDate3 

也许你的意思是：

SELECT E.id --assuming ID is the PK of Employee (E) 
    , E.monthDate 
    , coalesce(present, 0) as present 
    , coalesce(expected, 0) as expected 
    , coalesce(late, 0) as late 
FROM (SELECT distinct EmployeeID ID, month(Logintime) as monthdate 
     FROM tblAttendanceDetails) E 
LEFT JOIN (SELECT EmployeeId as id,count(Logintime) as present, month(Logintime) as monthDate 
      FROM tblAttendanceDetails 
      WHERE cast(Logintime as time)< cast('09:20' as time) 
      GROUP BY EmployeeId,month(Logintime)) as tb1 
    on E.ID = tb1.ID 
and E.Monthdate = t1.monthdate 
LEFT JOIN (SELECT EmployeeId,count(Logintime) as late, month(Logintime) as monthDate2 
      FROM tblAttendanceDetails 
      WHERE cast(Logintime as time)> cast('09:30' as time) 
      GROUP BY EmployeeId, month(Logintime)) as tb2 
    on E.id=tb2.EmployeeId 
and E.monthDate=tb2.monthDate2 
LEFT JOIN (SELECT EmployeeId,count(Logintime) as expected,month(Logintime) as monthDate3 
      FROM tblAttendanceDetails 
      WHERE cast(Logintime as time) between cast('09:20' as time) and cast('09:30' as time) 
      GROUP BY EmployeeId,month(Logintime)) as tb3 
    on E.id=tb3.EmployeeId 
and E.monthDate=tb3.monthDate3 

或者我们可以消除联接和子查询使用窗口功能。

SELECT EmployeeID as ID 
    , month(Logintime) as MonthDate 
    , sum(case when cast(Logintime as time) < cast('09:20' as time) 
       then 1 else 0 end) over (partition by month(Logintime),employeeID) as present 
    , sum(case when cast(Logintime as time)> cast('09:30' as time) 
       then 1 else 0 end) over (partition by month(Logintime),employeeID) as expected 
    , sum(case when cast(Logintime as time) between cast('09:20' as time) and cast('09:30' as time) 
       then 1 else 0 end) over (partition by month(Logintime),employeeID) as late 
FROM tblAttendanceDetails E 
--GROUP BY EmployeeID, month(LoginTime) -- is the group by needed don't think so since we're using the window functions and the case abstracts the logintime to 1/0 that is now summed...but not sure w/o testing. 

都能跟得上（约需要由集团关于SQL注释）的基础上：MSFT