Question

The following query

SELECT * FROM workshops 
WHERE workshop_zipcode LIKE '75___' 
  OR workshop_zipcode LIKE '77___' 
  AND workshop_category = 14 
  AND active = 1 
  AND workshop_date >= NOW() 
ORDER BY workshop_date ASC

don’t generate any errors, and actually work, but with a little problem : this part

AND workshop_date >= NOW()

don’t filter anything, itried to replace the comparative sign with an equal, and the same list is retrieved.

the two first AND works well, but the third don’t.

Answer 1

You need to parenthesize your OR condition Like this:

SELECT * FROM workshops 
WHERE (workshop_zipcode LIKE '75___' 
OR workshop_zipcode LIKE '77___')
AND workshop_category = 14 
AND active = 1 
AND workshop_date >= NOW() 
ORDER BY workshop_date ASC

Without parenthesis you are in essence calling this:

SELECT * FROM workshops 
WHERE workshop_zipcode LIKE '75___' 
OR (workshop_zipcode LIKE '77___'
AND workshop_category = 14 
AND active = 1 
AND workshop_date >= NOW())
ORDER BY workshop_date ASC

This is because AND is calculated before OR. See this reference

http://dev.mysql.com/doc/refman/5.0/en/operator-precedence.html