MySQL conditional query inside where clause

Question

I'm not sure if I'm missing something really obvious, but I keep getting a syntax error on this query. Even if I AM missing something obvious, I'd like to know if there is a smarter way of getting what I'm after.

Basically, the query asks for any rows tied to a user with a start_date between Monday and Friday. That works great. But then I added a conditional query in case there are any rows for that Saturday or Sunday. Note that the conditional query is checking for ANY users with a Saturday or Sunday, not the user in the main query:

SELECT user_id,
DATE_FORMAT(DATE(shift_start),'%m/%d/%Y') date, 
TIME_FORMAT(TIME(shift_start), '%h:%i %p') start,
TIME_FORMAT(TIME(shift_end), '%h:%i %p') end,
title   
FROM shifts
WHERE user_id = '$user_id'
AND DATE(shift_start) BETWEEN
DATE_SUB(DATE(NOW()), INTERVAL WEEKDAY(NOW()) DAY) AND
DATE_ADD(DATE(NOW()), INTERVAL 
    (SELECT
    IF( 
    COUNT(*) FROM shifts
    WHERE DATE(shift_start) BETWEEN
    DATE_ADD(DATE(NOW()), INTERVAL 5 - WEEKDAY(NOW()) DAY) AND
    DATE_ADD(DATE(NOW()), INTERVAL 6 - WEEKDAY(NOW()) DAY),
6, 4)) - WEEKDAY(NOW()) DAY)
ORDER BY shift_start

I'm actually pretty proud of how it works before it messes up with the IF part, but again, if there is an obviously better way doing this, I'm all ears.

Oh, and when this gets ironed out, the "Now()" will be replaced with a date variable set up in the php script (passed to it via GET).

---

Awesome job, benlumey. Here's what worked:

SELECT user_id,
       DATE_FORMAT(DATE(shift_start),'%m/%d/%Y') AS shift_start_date, 
       TIME_FORMAT(TIME(shift_start), '%h:%i %p') AS shift_start_time,
       TIME_FORMAT(TIME(shift_end), '%h:%i %p') AS shift_end_time,
       title
FROM shifts
WHERE user_id = '$user_id' AND 
DATE(shift_start) BETWEEN 
    DATE_SUB(DATE(NOW()), INTERVAL WEEKDAY(NOW()) DAY) 
    AND 
    DATE_ADD
    (
        DATE(NOW()), INTERVAL
        (
        SELECT IF(COUNT(*),6,4)
        FROM shifts
        WHERE DATE(shift_start) BETWEEN 
            DATE_ADD(DATE(NOW()), INTERVAL 5 - WEEKDAY(NOW()) DAY) 
            AND 
            DATE_ADD(DATE(NOW()), INTERVAL 6 - WEEKDAY(NOW()) DAY)
        ) - WEEKDAY(NOW()) DAY
    )

Answer 1

Try this subquery:

(SELECT 
    IF(COUNT(*) > 0, 6, 4)) - WEEKDAY(NOW()) DAY) 
    FROM shifts 
    WHERE DATE(shift_start) BETWEEN
    DATE_ADD(DATE(NOW()), INTERVAL 5 - WEEKDAY(NOW()) DAY) AND
    DATE_ADD(DATE(NOW()), INTERVAL 6 - WEEKDAY(NOW()) DAY)

Two things I've done

• made it look like a normal query, the from and where can't go inside the if as far as i'm aware.
• Put a condition in the if, don't think mysql will automatically take 0 as false and >0 as true.

Answer 2

this falls apart around here:

    (SELECT
    IF( 
       COUNT(*) FROM shifts
    WHERE DATE(shift_start) BETWEEN

The count statement won't work.

What are you trying to do? You need a clear statement of what you are trying to accomplish here.

This is my swag at it:

 (SELECT
    IF( 
      (select COUNT(*) FROM shifts
       WHERE DATE(shift_start) BETWEEN
       DATE_ADD(DATE(NOW()), INTERVAL 5 - WEEKDAY(NOW()) DAY) AND
       DATE_ADD(DATE(NOW()), INTERVAL 6 - WEEKDAY(NOW()) DAY))>0,6,4)
 ) - WEEKDAY(NOW()) DAY

But without knowing what you are trying to do I'm not sure.