Retrieve list of ids by comparing total -vs- specified status - mysql

Question

I have a list of clients. Each client can have several activities (0..*). Each activity contains a status `is_completed` which is a Boolean (True/False).
I need to retrieve the list of clients that have all activities completed:
if a client has all its activities completed, I keep him.
if a client has not all its activities completes, I ignore him.
I wrote an SQL query that does the job but I am not convinced that it is optimized:
SELECT DISTINCT cc.client_id
FROM clients_clientactivity AS cc
LEFT JOIN clients_client AS c ON (c.id = cc.client_id)
WHERE c.client_type_id = 2
AND (
SELECT COUNT(cc1.id) FROM clients_clientactivity AS cc1 WHERE cc1.client_id = cc.client_id
) = (
SELECT COUNT(cc2.id) FROM clients_clientactivity AS cc2 WHERE cc2.is_completed = True AND cc2.client_id = cc.client_id
);
How can I improve it ?
Thank you for your help.

Answer 1

You could use a not in select for the not true
SELECT DISTINCT cc.client_id
FROM clients_clientactivity AS cc
LEFT JOIN clients_client AS c ON (c.id = cc.client_id)
WHERE c.client_type_id = 2
AND cc.client_id NOT IN (
SELECT cc2.client_id
FROM clients_clientactivity AS cc2
WHERE cc2.is_completed != True
)

Answer 2

I would use aggregation and having:
SELECT c.id
FROM clients_clientactivity ca JOIN
clients_client c
ON c.id = ca.client_id
WHERE c.client_type_id = 2
GROUP BY c.id
HAVING COUNT(*) = SUM(ca.iscompleted)
Your WHERE clause converts the LEFT JOIN to an INNER JOIN, so I removed the LEFT JOIN.

Answer 3

Let's simplify even further:
SELECT client_id
FROM clients_clientactivity
WHERE MIN(is_completed) = TRUE
GROUP BY client_id
(TRUE==1, FALSE==0)
Subqueries are often slow. NOT IN ( SELECT ... ) is really bad (unless the optimizer has magically gotten smarter).
You did not explain how client_type_id = 2, but maybe something like:
clients_client
SELECT a.client_id
FROM clients_client AS c
JOIN clients_clientactivity AS a ON (c.id = a.client_id)
WHERE MIN(a.is_completed) = TRUE
AND c.client_type_id = 2
GROUP BY a.client_id
If performance is a problem, then:
c needs INDEX(client_type_id, id)
a needs INDEX(client_id, is_completed)