MySQL JOIN / UNION DISTINCT issue - mysql

Question

I am working on a project where users need to have permissions based on which department they are connected to.
So now I am trying to do a query that will show me users that have all necessary permissions based on the users department_id (users that do not have all necessary permissions shall not be displayed in the result).
I have been trying lot of different things (different type of JOINS, sub queries w/where in, exists and union distinct) without luck, this kind of query is next level for me and challenges my logical thinking.
Tables:
users
id
first_name
last_name
department_id
permissions
id
name
departments (relation to groups and categories based on department)
id
name
category_id
group_id
categories
id
name
groups
id
name
departments_permissions (permission requirement)
department_id
permission_id
categories_permissions (permission requirement)
category_id
permission_id
groups_permissions (permission requirement)
group_id
permission_id
users_permissions (users have permissions here)
user_id
permission_id
Department
A department CAN (not required) have many permissions (departments_permissions).
A department CAN (not required) have a category.
A department CAN (not required) have a group.
Category
A category CAN (not required) have many permissions (categories_permissions).
Group
A group CAN (not required) have many permissions (groups_permissions).
Important side note
departments_permissions, categories_permissions and groups_permissions can contain one or more of the same permission_id's, therefore we have to select distinct values.
Example data
https://pastebin.com/BvhAznpY
My latest query attempt:
SELECT
`users`.id,
`users`.first_name,
`users`.last_name,
`users`.department_id
FROM
`users`
INNER JOIN
`departments` ON `users`.department_id = `departments`.id
INNER JOIN
`users_permissions` ON `users`.id = `users_permissions`.user_id
INNER JOIN
(
SELECT permission_id FROM departments_permissions WHERE department_id = departments.id
UNION DISTINCT
SELECT permission_id FROM categories_permissions WHERE category_id = departments.group_id
UNION DISTINCT
SELECT permission_id FROM groups_permissions WHERE group_id = departments.group_id
) AS tblPermissionsRequired ON `users_permissions`.permission_id = `tblPermissionsRequired`.permission_id
GROUP BY
`users_permissions`.user_id;

Answer 1

Build 2 tables (sub-queries) to list
all the permission a user required (i.e. user_permissions)
all the permission a user have (i.e. 3 unions similar to what you have done)
Join them and group by id would find the the number of required and how many of them are given already.
Finally, add a filter clause (using HAVING). Then you got the list of user ID :)
select
up.user_id,
max(u.first_name) as first_name,
max(u.last_name) as last_name,
count(up.permission_id) as permission_required,
count(perm.permission_id) as permission_have
from
users u
join
users_permissions up on u.id = up.user_id
left join
(
SELECT users.id as user_id, permission_id
FROM users
INNER JOIN departments ON users.department_id = departments.id
INNER JOIN departments_permissions on departments_permissions.department_id = departments.id
UNION
SELECT users.id, permission_id
FROM users
INNER JOIN departments ON users.department_id = departments.id
INNER JOIN categories_permissions on categories_permissions.category_id = departments.category_id
UNION
SELECT users.id, permission_id
FROM users
INNER JOIN departments ON users.department_id = departments.id
INNER JOIN groups_permissions on groups_permissions.group_id = groups_permissions.group_id
) perm
on up.user_id = perm.user_id and up.permission_id = perm.permission_id
group by up.user_id
having count(up.permission_id) = count(perm.permission_id)

Answer 2

I think what you need is something like this:
SELECT u.first_name,u.last_name,p.name
FROM users u, user_permissions up, permissions p
WHERE u.id=up.user_id AND
up.permission_id=p.id
UNION
SELECT u.first_name,u.last_name,p.name
FROM users u, departments d, departments_permission dp, permissions p
WHERE u.department_id=d.id
AND d.id=dp.department_id
AND dp.permission_id=p.id
UNION
SELECT u.first_name,u.last_name,p.name
FROM users u, departments d, categories_permission cp, permissions p
WHERE u.department_id=d.id
AND d.category_id=cp.category_id
AND cp.permission_id=p.id
UNION
SELECT u.first_name,u.last_name,p.name
FROM users u, departments d, groups_permission gp, permissions p
WHERE u.department_id=d.id
AND d.group_id=gp.group_id
AND gp.permission_id=p.id
Here's a hint:
Create a VIEW with the query above
Do a SELECT DISTINCT * on the view

Answer 3

This following script should work-
SELECT A.id,A.first_name,A.last_name,A.department_id
FROM
(
SELECT U.*,
A.Dept_id AS Dept_ID,
A.permission_id AS [Dept_Wise_Permissiion_List],
UP.permission_id
FROM users U
INNER JOIN (
SELECT D.id Dept_id,CP.permission_id
FROM departments D INNER JOIN categories_permissions CP ON D.category_id = CP.category_id
UNION ALL
SELECT D.id Dept_id,GP.permission_id
FROM departments D INNER JOIN groups_permissions GP ON D.group_id = GP.group_id
UNION ALL
SELECT D.id Dept_id, DP.permission_id
FROM departments D INNER JOIN departments_permissions DP ON D.id = DP.department_id
) A ON U.department_id =A. Dept_id
LEFT JOIN users_permissions UP
ON U.id = UP.user_id AND A.permission_id = UP.permission_id
)A
GROUP BY A.id,A.first_name,A.last_name,A.department_id
HAVING COUNT(ISNULL(A.permission_id,1)) = COUNT(A.permission_id)