Question

I have a table:

Table Teams

Id_team         member_1         member_2         member_3
1                Alice            Ben
2                Ben
3                Charles          Alice            Ben
4                Ben              Alice

I will need to know in how many different teams Alice is a member (doesn’t count if she is the first member, second or third). In my sample, the right answer is 2 (with Ben in Id_team 1 and 4, with Ben and Charles in Id_team = 3). Thank you!

Answer 1

You have to count “alices” in each column separately to ensure distinct oer column

What you appear to checking is “

SELECT
   COUNT(DISTINCT CASE WHEN member_1 = 'Alice' THEN member_1 END) +
   COUNT(DISTINCT CASE WHEN member_2 = 'Alice' THEN member_2 END) +
   COUNT(DISTINCT CASE WHEN member_3 = 'Alice' THEN member_3 END)
FROM tablename
WHERE 'Alice' IN(member_1, member_2, member_3);

Update: fixed COUNT