我可以 select SQL 中的一组平均值吗

Question

我可以 select 一组基于 SQL 字段的平均值吗？类似于：

SELECT 
    AVG(Salary WHERE department = 1) as AvgDept1,
    AVG(Salary WHERE title = 1) as AvgTitle1,
    AVG(TimeOnJob WHERE title = 1 and department = 1) as AvgTime1
FROM
    Employees

我知道这类似于带有 GROUP BY 的 AVG，但我不知道如何从中获取三个值。

Answer 1

这些看起来像三个独立的查询，如果你想把它们捆绑成一个 select 你可以这样做：

SELECT 
   (SELECT AVG(Salary) WHERE department = 1 FROM Employees) AS AvgDept1,
   (SELECT AVG(Salary)  WHERE title = 1 FROM Employees) AS AvgTitle1
   (select AVG(TimeOnJob) WHERE title = 1 and department = 1 FROM Employees) AS AvgTime1

我可以 select SQL 中的一组平均值吗

Can I select a set of averages in SQL

sql-server-2008-r2