Reputation: 1912
I am doing product filter the point is the more specific the user select the products the less results should appear. At he moment I am writing multiple queries and storing in arrays and checking for array intersect, but the result is opposite, which means when user apply more filters, i will show more products.
So i am thinking there could be a SQL command which I don't know!
simplified example:
------------
table "filter"
------------
product
Spec
value
------------
Sample data
------------
book1,page,200
book1,cover,leather
book1,language,en
book2,page,300
book2,cover,paper
book2,language,de
book3,page,150
book3,cover,hard
book3,language,en
SELECT `product` FROM `filter` where ...
how do I select (page=200 and langauge=en)?
Upvotes: 0
Views: 591
Reputation: 43718
Another alternative, but less elegant. I just wanted to show another way of doing it.
SELECT DISTINCT product
FROM filter f
WHERE
EXISTS (SELECT 1 FROM filter WHERE spec = 'language' AND value = 'en' AND product = f.product)
AND EXISTS (SELECT 1 FROM filter WHERE spec = 'page' AND value = 200 AND product = f.product);
Upvotes: 1
Reputation: 92785
If understand correctly you are probably looking for something like this
SELECT product
FROM filter
WHERE (spec = 'page' AND value = '200')
OR (spec = 'language' AND value = 'en')
GROUP BY product
HAVING COUNT(*) = 2 -- 2 here represents number of spec-value pairs
Output:
| PRODUCT |
-----------
| book1 |
Upvotes: 3