Count number of records with specific values - sql

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

Answer 2

Okay, so you want to same teams with different positions (e.g. Alice&Ben, Ben&Alice) count as one.
To do this, order the members in ascending order for alice in every position, and count the results (this returns 2 to your example):
SELECT COUNT(*) FROM
(
SELECT
least( member_2, member_3) AS l,
greatest(member_2, member_3) AS g
FROM teams
WHERE
member_1 = 'Alice'
UNION
SELECT
least( member_1, member_3) AS l,
greatest(member_1, member_3) AS g
FROM teams
WHERE
member_2 = 'Alice'
UNION
SELECT
least( member_1, member_2) AS l,
greatest(member_1, member_2) AS g
FROM teams
WHERE
member_3 = 'Alice'
) q
;
Note that this can only be done to the special case of 3 member teams, because least and greatest can select the two other members - for member coun of 4 and greater, a more complex solution is needed.

Answer 3

You can try to concatenate the fields (sorted alphabetically) in order to turn them into a list of strings.
Then run a distinct on this list (so it will list all separate teams)
Then search how many strings contains Alice
From this the hardest is the "concat alphabetically", as I couldn't really find any good function to do it, but a GROUP_CONCAT with a separate SELECTs and UNIONs to convert the fields into rows should do it:
SELECT COUNT(*)
FROM (
SELECT DISTINCT team_as_string
FROM (
SELECT id tid, GROUP_CONCAT(q ORDER BY q ASC SEPARATOR ',') team_as_string
FROM (
SELECT id, member_1 q FROM teams
UNION SELECT id, member_2 q FROM teams
UNION SELECT id, member_3 q FROM teams
/* add more fields if needed */
) c
GROUP BY tid
) b
) a
WHERE team_as_string LIKE '%Alice%'
I haven't checked it for syntax errors, but it should be fine logically. Tested and gives the correct answer (2)
This can be enhanced for more members, if needed.
Of course if the members are in a separate join table, then the whole group_concat part can be simplified.

Answer 4

I will need to know in how many different teams Alice is a member
Try this:
SELECT 'Alice', COUNT(id_team)
FROM tablename
WHERE 'Alice' IN(member_1, member_2, member_3);
The result:
| ALICE | THECOUNT |
--------------------
| Alice | 3 |
Fiddle Demo.
If id_team is not unique, use COUNT(DISTINCT id_team).