Question

I have a product table with a relationship to color table

a product can have many colors…
exp: Product A: has red, green blue yellow.

How may I select products which contain at least red and green(dynamic)?

example:

Product: RED GREEN - PASS
Product: RED GREEN YELLOW - PASS
Product: RED YELLOW - FAIL

Prefer join table solution or independent sub queries only

this problem is related to
One to Many search using AND condition

I’m trying to tackle it from fundamentals.

thanks in advance

Answer 1

Something like this should work

SELECT product.name
  FROM product
       JOIN color USING (product_id)
 WHERE color.name IN ('red', 'green')
 GROUP BY product.name
HAVING COUNT(DISTINCT color.name) = 2

where the HAVING clause specifies the number of items in the list. So if you wanted products that are available in red, green, and yellow, you’d change the query to

SELECT product.name
  FROM product
       JOIN color USING (product_id)
 WHERE color.name IN ('red', 'green', 'yellow')
 GROUP BY product.name
HAVING COUNT(DISTINCT color.name) = 3