Question

Let’s say I have a table with the following columns:
EmployeeID, PayEntity, HourWorked, Date where PayEntity can be 1:Normal, 2:OverTime, etc How can I get the average of Hours worked for a period of time for example if we do have on my table those data:

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

The average for this date must be (40+5)+30/2 -- 37.5

Answer 1

Try using a subselect where you find the total hours for each employee per day, and an outer select where you calculate the average per day:

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

See it working online: sqlfiddle