获取平均此查询

Question

比方说，我有如下的表： EmployeeID, PayEntity, HourWorked, Date其中PayEntity can be 1:Normal, 2:OverTime, etc我怎样才能小时的平均工作了一段时间，例如，如果我们确实有我的表的数据：

1, 1, 40, 7/25/12 
1, 2, 5, 7/25/12 
2, 1, 30, 7/25/12 

平均此日期必须(40+5)+30/2 -- 37.5

Answer 1

尝试使用你找到每天每个员工的总小时数子查询和外选择您计算出平均每天：

SELECT Date, AVG(HourWorked) AS HourWorked 
FROM 
(
    SELECT Date, SUM(HourWorked) AS HourWorked 
    FROM yourtable 
    GROUP BY EmployeeId, Date 
) T1 
GROUP BY Date 

看到它联机工作：sqlfiddle

Answer 2

按照同样的思路，但不知道有一个AVG功能

SELECT employee_id, total_hours, days, total_hours/days as average, 
FROM (
    SELECT employee_id, SUM(hours) as total_hours, COUNT(date) as days FROM `employee_hours_table` GROUP BY `employee_id` 
) data