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CREATE TABLE `group_users`( group_id INT, user_id INT );
INSERT INTO `group_users` VALUES
( 1, 2),
( 1, 37),
( 1, 38),
( 3, 14),
( 8, 2),
( 8, 24),
( 8, 27);
CREATE TABLE `groups`( group_id INT, groupname VARCHAR(15) );
INSERT INTO `groups` VALUES
( 1, 'Sales'),
( 3, 'Marketing'),
( 8, 'Production ');
SELECT g.group_id, g.groupname, gu.group_members
FROM `groups` g
JOIN (SELECT GROUP_CONCAT(DISTINCT user_id ORDER BY user_id)
AS group_members, group_id
FROM `group_users`
GROUP BY group_id
HAVING COUNT(CASE WHEN user_id = 2 THEN 1 END) > 0
) gu
ON g.group_id = gu.group_id
ORDER BY gu.group_id;
| group_id | groupname | group_members |
|---|---|---|
| 1 | Sales | 2,37,38 |
| 8 | Production | 2,24,27 |