如何在SQL Server 2008中对此查询进行子查询？

Question

Calculate the minimum salary for exempt employees and the average salary for non-exempt employees in a SINGLE SQL statement. Use subqueries to incorporate both elements in the query. It should look something like:

Min Exempt Salary   Average Non-Exempt Salary
47,000                           35,271

I know how to do it separate but cannot figure how to do it as it stated above , this is the statments I have.

SELECT jobs1.exempt_nonexempt_status,
       Min (employees.salary)AS Minimal_Exempt_Salary
FROM   employees
       LEFT JOIN jobs1
              ON employees.job_title = jobs1.job_title
WHERE  jobs1.exempt_nonexempt_status = 'Exempt'
GROUP  BY jobs1.exempt_nonexempt_status

SELECT jobs1.exempt_nonexempt_status,
       Avg (employees.salary)AS Average_Non_Exempt_Salary
FROM   employees
       LEFT JOIN jobs1
              ON employees.job_title = jobs1.job_title
WHERE  jobs1.exempt_nonexempt_status = 'Non-exempt'
GROUP  BY jobs1.exempt_nonexempt_status 

Answer 1

Try this:

SELECT 
    MIN(CASE WHEN J.exempt_nonexempt_status = 'Exempt'
             THEN E.Salary
             END) AS Minimal_Exempt_Salary,

    SUM(CASE WHEN J.exempt_nonexempt_status = 'Non-exempt'
             THEN E.Salary
             END) AS Average_Non_Exempt_Salary

FROM Employees E
LEFT JOIN JOBS1 J ON J.job_title = E.job_title
WHERE J.exempt_nonexempt_status IN ('Exempt', 'Non-exempt')

Answer 2

A normal way to do this would be:

select  j.exempt_nonexempt_status
,       avg(case when j.exempt_nonexempt_status='Non-exempt' then e.salary end) 
            as Average_Non_Exempt_Salary
,       min(case when j.exempt_nonexempt_status='Exempt' then e.salary end)
            as Minimal_Exempt_Salary
from    Employees e 
left join 
        jobs1 j
on      e.job_title = j.job_title
group by 
        j.exempt_nonexempt_status

But that doesn't use subqueries. Another way is to wrap your two queries in an outer select:

select  (
        select MIN (employees.salary)
        from Employees left join jobs1
        on employees.job_title = jobs1.job_title
        where jobs1.exempt_nonexempt_status='Exempt'
        group by jobs1.exempt_nonexempt_status
        ) as MinimalExemptSalary
,       (
        select avg (employees.salary)
        from Employees left join jobs1
        on employees.job_title = jobs1.job_title
        where jobs1.exempt_nonexempt_status='Non-exempt'
        group by jobs1.exempt_nonexempt_status
        ) as AverageNonExemptSalary