请问这个SQL语句怎么写.

Question

我试了半天,写不出来,本人SQL掌握较差.

Answer 1

select e.*,HowManyCustome =(select Count(CustomeId) from Custome where employeeID = 1)
from employee e
where e.employeeid = 1

Answer 2

select employee.EmployeeId,EmployeeName,EmployeeTelephone,EmployeeAddress,count(CustomeId) from employee left join custome on employee.EmployeeId=custome.EmployeeId group by employee.EmployeeId

Answer 3

select a.EmployeeId,a.EmployeeName,a.EmployeeTelephone,a.EmployeeAddress,b.cuscount
from Employee as a left join (select Employeeid ,count(*) cuscount from Custome group by Employeeid) as b on a.Employeeid =b.Employeeid

Answer 4

select employee.EmployeeId,EmployeeName,EmployeeTelephone,EmployeeAddress,count(CustomeId) from employee left join custome on employee.EmployeeId=custome.EmployeeId group by employee.EmployeeIdselect a.EmployeeId,a.EmployeeName,a.EmployeeTelephone,a.EmployeeAddress,b.cuscount
from Employee as a left join (select Employeeid ,count(*) cuscount from Custome group by Employeeid) as b on a.Employeeid =b.Employeeid这两句结果是有区别的,第一种较好一些,
第一种在客户总数这里,如果custome表没有记录的话,这里显示0,而第二种这里显示null