SQL JOIN多个多对多表

Question

Using MySql, I will like to join multiple many-to-many tables (users_roles and roles_permissions) by a given user id. But there is something wrong with my query because it gives an error as below.

#1054 - Unknown column 'users_roles.role_id' in 'on clause'

SELECT roles.name, permissions.name
FROM users_roles, roles_permissions
JOIN roles ON users_roles.role_id = roles.id
JOIN permissions ON roles_permissions.permission_id = permissions.id
WHERE users_roles.user_id = 1 AND roles_permissions.role_id = roles.id 

My table structure inside PHPMyAdmin is as follow:

Table users_roles
id | user_id | role_id

Table roles_permissions
id | role_id | permissions_id

Table roles
id | name | description

Table permissions
id | name | description

Answer 1

I think you should use a set of proper join

SELECT roles.name, permissions.name
FROM users_roles 
JOIN roles ON users_roles.role_id = roles.id
JOIN roles_permissions on roles_permissions.role_id = users_roles.role_id
JOIN permissions ON roles_permissions.permission_id = permissions.id
WHERE users_roles.user_id = 1 

Answer 2

You can use the below query, You can do it in two ways,

Using JOINS

SELECT roles.name, permissions.name
FROM users_roles INNER JOIN roles_permissions
ON (users_roles.role_id = roles.id)
INNER JOIN permissions ON (roles_permissions.permission_id = permissions.id)
AND users_roles.user_id = 1 
AND roles_permissions.role_id = roles.id;

Using Alias

SELECT R.name, P.name from
users_roles UR, roles_permissions RP,  permissions P, roles R
WHERE UR.role_id = R.id AND
RP.role_id = UR.role_id AND
RP.permission_id = P.id
UR.user_id = 1;

But using JOINS is the efficient way. Hope you got it. Any help, feel free to ask