Question

I have three tables:

items:

id   name
4   Item Blue, L
2   Item Blue, S
6   Item Green
8   Item L
9   Item Red, Blue, Green, S, M, L
5   Item Red, L
3   Item Red, M
1   Item Red, S
7   Item S

options:

id   group   name
1   1   red
2   1   blue
3   1   green
4   2   s
5   2   m
6   2   l

items_has_options:

item_id   options_id
1   1
1   4
2   2
2   4
3   1
3   5
4   2
4   6
5   1
5   6
6   3
7   4
8   6
9   1
9   2
9   3
9   4
9   5
9   6

How can i select items which have options: (red or blue or green) and (s)? I need to choose items which have some options from different groups. Options may have many groups, not only two. Result must be:

2   Item Blue, S
9   Item Red, Blue, Green, S, M, L
1   Item Red, S

Answer 1

Not sure this will work but it might get you started..

SELECT DISTINCT i.id, i.name FROM items i
INNER JOIN items_has_options ihs1 ON
    i.id = ihs1.item_id
INNER JOIN items_has_options ihs2 ON
    i.id = ihs2.item_id
INNER JOIN options o1 ON
    ihs1.options = o1.id AND (o1.name = "red" OR o1.name = "blue" OR o1.name="green")
INNER JOIN options o2 ON
    ihs2.options = o2.id AND o2.name = "s"

The idea is that you join with the options table twice, once for color and once for size.
You need the distinct since you will get duplicate rows from o1…