MySQL query - join 3 tables together, group by one column and count for the other 2
Here are examples of the 3 tables I'm working with.
Teams
+----+------+
| id | name |
+----+------+
| 1 | abc |
| 2 | def |
| 3 | ghi |
+----+------+
Members
+----+-----------+----------+---------+
| id | firstname | lastname | team_id |
+----+-----------+----------+---------+
| 1 | joe | smith | 1 |
| 2 | jared | robinson | 1 |
| 3 | sarah | cole | 3 |
| 4 | jaci | meyers | 2 |
+----+-----------+----------+---------+
Goals
+----+-----------+
| id | member_id |
+----+-----------+
| 1 | 3 |
| 2 | 2 |
| 3 | 2 |
| 4 | 3 |
| 5 | 1 |
+----+-----------+
And I'm trying to get a query that outputs something like this ...
Output
+--------+----------------+-------------+
| t.name | Count(members) | Count(goals)|
+--------+----------------+-------------+
| abc | 2 | 3 |
| def | 1 | 2 |
| ghi | 1 | 0 |
+--------+----------------+-------------+
This is the closest I've come, but when I use the group by in the subquery I get "Subquery returns more than 1 row".
select t.name, count(*),
(select count(*)
from teams t
inner join members m on m.team_id = t.id
group by t.id)
from teams t
inner join members m on m.team_id = t.id
inner join goals g on g.member_id = m.id
group b开发者_StackOverflow中文版y t.id
Based on my understanding, here is the query that I come up with:
SELECT name, membersCount, IFNULL(totalCount, 0) goalsCount FROM
(
SELECT m.team_id, SUM(innerQuery.goalsCount) totalCount
FROM (
SELECT m.id memberId, COUNT(*) goalsCount
FROM Members m
JOIN Goals g
ON m.id = g.member_id
GROUP BY member_id
) innerQuery
JOIN Members m
ON innerQuery.memberId = m.id
GROUP BY m.team_id
) inner_1
RIGHT JOIN
(
SELECT t.id, t.name, COUNT(*) membersCount
FROM Teams t
JOIN Members m
ON t.id = m.team_id
GROUP BY team_id
) inner_2
ON inner_1.team_id = inner_2.id
The breakdown of the query:
#1. Get the member ID with its associated goals count (innerQuery)
SELECT m.id memberId, COUNT(*) goalsCount
FROM Members m
JOIN Goals g
ON m.id = g.member_id
GROUP BY member_id
#2. Get the team id for with the total SUM of the goals (inner_1)
SELECT m.team_id, SUM(innerQuery.goalsCount) totalCount
FROM (
.... Sub-query in step 1
) innerQuery
JOIN Members m
ON innerQuery.memberId = m.id
GROUP BY m.team_id
#3. Get total members count per team (inner_2)
SELECT t.id, t.name, COUNT(*) membersCount
FROM Teams t
JOIN Members m
ON t.id = m.team_id
GROUP BY team_id
#4. RIGHT JOIN inner_1 and inner_2 (since there will be NULL) and use IFNULL to check and replace that 0
SELECT name, membersCount, IFNULL(totalCount, 0) goalsCount FROM
(
.... Sub-query in step 2
) inner_1
RIGHT JOIN
(
.... Sub-query in step 3
) inner_2
ON inner_1.team_id = inner_2.id
加载中,请稍侯......
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