SQL for applying conditions to multiple rows in a join

Question

I think I found the answer to my question, I\'m just unsure of the syntax, I keep getting SQL errors.

Basically, I want to do the opposite of IN. Take this example:<

Answer 1

SELECT Users.id, count(tags.*) as tagCount
FROM Users Inner join tags
ON tags.user_id = users.id
WHERE tags.name='tag1' OR tags.name='tag2'
GROUP BY Users.id
HAVING count(tags.*) = 2

Answer 2

Give this a try

SELECT *
FROM users
INNER JOIN tags ON tags.user_id = users.id
WHERE users.id in
    (
    SELECT user_id
    FROM tags
    WHERE name IN ('tag1', 'tag2')
    GROUP BY user_id
    HAVING COUNT(*) = 2
    )

Answer 3

select * from users u
where 2 = (select count(*) from tags t where t.user_id = u.id and name in ('tag1','tag2'))

Assuming that any given tag can only be present once per user.

Answer 4

You'll want to join the tags table again.

SELECT * FROM users
INNER JOIN tags as t1 on t1.user_id = users.id and t1.name='tag1'
INNER JOIN tags as t2 on t2.user_id = users.id and t2.name='tag2'

Answer 5

You'll need to check for the existence of two rows, rather than being able to do a simple IN (which will only check the values within each joined record). Maybe something like:

SELECT * 
from users
WHERE EXISTS (SELECT NULL FROM tags WHERE tags.user_id = users.id AND tags.name = 'tag1')
  AND EXISTS (SELECT NULL FROM tags WHERE tags.user_id = users.id AND tags.name = 'tag2');