Question

我有三张表出席，员工，部门员工表

EmiId -Name -SectorId
123     ABC   1
231     BCD   2
125    WER    1

考勤

AttId -EmpId -Dt
1      123    12/12/2014 9:00
2      231    12/12/2014 10:00

扇区

SectorId -SectorName
1          North Sector
2          East Sector

我的查询是

  SELECT COUNT(Attendance.Emp_Id) as AttCount,(select COUNT(*) from Employee) as EmpCount
FROM  Employee  INNER JOIN
               Sector ON Employee.SectorId = Sector.SectorId INNER JOIN
               Attendance ON Employee.EmpId = Attendance.EmpId          
               group by Sector.SectorId

并且我为两者保持相同数量的员工，因此(select COUNT(*) from Employee) - EmpCount似乎是不正确的。我继续为这两个部门获得相同的数字。虽然Attcount似乎工作得很好。请帮忙。提前谢谢。

Answer 1

也许你需要参加LEFT JOIN

SELECT COUNT(Attendance.Emp_Id),(select COUNT(*) from Employee)
FROM  Employee JOIN Sector ON Employee.SectorId = Sector.SectorId 
               LEFT JOIN Attendance ON Employee.EmpId = Attendance.EmpId          
group by Sector.SectorId

Answer 2

您只需从同一张表中选择计数 - 不要指望其他结果。

也许有人可以做得更好

SELECT COUNT(Attendance.Emp_Id),COUNT(case when Employee.empid=attendance.attid then 1 else 0 end)
    FROM  Employee JOIN Sector ON Employee.SectorId = Sector.SectorId 
                   LEFT JOIN Attendance ON Employee.EmpId = Attendance.Emp_Id          
    group by Sector.SectorId

组在三个表之间加入以获得百分比

2 个答案: