Recursive CTE Multiple Levels [duplicate]

Question

This question already has an answer here:

Making a recursive CTE like query, but for many records (1 answer)

Closed 4 months ago.

I have a table showing which roles recursively grant access to which resources within a database. For example:

The Default_Role grants access to the App_Role, the App_Role grants access to the Security_Role, and the Security_Role grants access to three tables (customers, sales, users). So a member of the Default_Role is granted all of these, but Default_Role is not granted access to the Sys_Role, and is not granted access to the System or Admin tables.

CREATE TABLE SQLTest(
     DBName     NVARCHAR(100) NULL
    ,Privilege    NVARCHAR(100) NULL
    ,PrivilegeType NVARCHAR(100) NULL
    ,PrivilegeDetail NVARCHAR(100) NULL
    ,TableName NVARCHAR(100) NULL
)

INSERT INTO SQLTest
VALUES 
('TSDB','Default_Role','Role','App_Role',NULL),
('TSDB','App_Role','Role','Security_Role',NULL),
('TSDB','Sys_Role','Role','Security_Role',NULL),
('TSDB','Security_Role','Table','Customers','Customers'),
('TSDB','Security_Role','Table','Sales','Sales'),
('TSDB','Security_Role','Table','Users','Users'),
('TSDB','Sys_Role','Table','System','System'),
('TSDB','Sys_Role','Table','Admin','Admin')

What is the best way to flatten this out so you can see all the access (roles and tables) granted to the Default_Role, without showing additional access not granted to the Default_Role? Like this:

Tried putting together this example, but doesn't work.

http://www.sqlfiddle.com/#!18/f9a27/2

Answer 1

As CTE's are for the first test quite difficult to understand, i wrote a approach, with all Levels at the end

The Option at the end is nit needed, but to reduce espeically when you are trying to figure out what happens, you shoukld add it at a low number

WITH MyTest as
(
  SELECT P.DBName, P.Privilege,p.PrivilegeType,P.PrivilegeDetail,P.TableName , CAST(P.PrivilegeDetail AS VarChar(Max)) as Level
  FROM SQLTest P
  WHERE P.Privilege = 'Default_Role'

  UNION ALL

  SELECT P1.DBName, P1.Privilege,p1.PrivilegeType,P1.PrivilegeDetail,p1.TableName , CAST(P1.PrivilegeDetail AS VarChar(Max)) + ', ' + M.Level
  FROM SQLTest P1  
  INNER JOIN MyTest M
  ON M.PrivilegeDetail = P1.Privilege
 )
SELECT * From MyTest

OPTION (MAXRECURSION 50);

REsult

DBName  Privilege       PrivilegeType   PrivilegeDetail     TableName   Level
TSDB    Default_Role    Role            App_Role            (null)       App_Role
TSDB    App_Role        Role            Security_Role       (null)       Security_Role, App_Role
TSDB    Security_Role   Table           Customers           Customers    Customers, Security_Role, App_Role
TSDB    Security_Role   Table           Sales               Sales        Sales, Security_Role, App_Role
TSDB    Security_Role   Table           Users                Users       Users, Security_Role, App_Role