Question

I have 3 tables : users, roles and roles_users (roles_users is a relational table with 2 columns, user_id and role_id)

A user can have many roles, through the roles_users table.

How can I build a select query that will not select a user, if he has a specific role.

To illustrate :

• a super admin user has the super admin , admin, login and publisher roles.

• an admin user has the admin, login and publisher roles.

• a publisher user has the login and publisher roles.

I want to select all the users that do not have the super admin role.
In other words, if a user has the super admin role, then do not select it.

How can I achieve this in SQL ?

Edit : Here is the query that worked for me at the end : (thanks to András Ottó’s answer)

SELECT DISTINCT(users.id), users.*
FROM users
INNER JOIN roles_users on users.id = roles_users.user_id
INNER JOIN roles ON roles_users.role_id = roles.id
WHERE NOT EXISTS(SELECT roles_users.user_id FROM roles_users
      WHERE roles_users.user_id = users.id AND roles_users.role_id = 2)

Answer 1

In Sql Server on in Oracle you can try:

SELECT users.*, roles.roleName
FROM users
INNER JOIN roles_users on users.userid = roles_users.userid
INNER JOIN roles ON roles_users.roleID = roles.roleID
WHERE NOT EXISTS(SELECT roles_users.userID FROM roles_users
      WHERE roles_users.userID = users.userid AND roleName = 'super admin')

Here is an SQL Fiddle.