Question

I think I’m pretty close on this query, but can’t seem to crack it, and I’m not sure if I’ve got the most efficient approach.

I am trying to find a day where a user is not booked from a range of dates where they are booked.

Think staff scheduling. I need to find who is available to work on Tuesday, and is working on other days this week.

My query currently looks like this

SELECT employees.uid, name, date
FROM employees
LEFT JOIN storelocation ON employees.uid = storelocation.uid
LEFT JOIN schedule ON emplyees.uid = schedule.uid
WHERE slid =9308
AND date
BETWEEN '2009-11-10'
AND '2009-12-20'
AND NOT
EXISTS (

SELECT uid
FROM schedule
WHERE date = '2009-11-11'
)

If I don’t include the ‘Not Exists’, I get 1500 results
If I use only the Select form the ‘Not Exists’, I get 200 results, so both of those queries work independently.
However, my query as I’ve written it returns 0 results.

Answer 1

You might want to try something more like this:

SELECT employees.uid, name, date
FROM users
LEFT JOIN storelocation ON employees.uid = storelocation.uid
LEFT JOIN schedule ON emplyees.uid = schedule.uid
WHERE slid =9308
AND date BETWEEN '2009-11-10' AND '2009-12-20'
AND employees.uid NOT IN (
    SELECT uid
    FROM schedule
    WHERE date = '2009-11-11'
)