Compare perms in PostgreSQL

The following script compares permissions between two roles in PostgreSQL

WITH role_permissions AS (
  SELECT
    n.nspname AS schema_name,
    c.relname AS object_name,
    c.relkind AS object_type,
    p.rolname AS role_name,
    COALESCE(ac.privilege_type, '') AS privilege
  FROM
    pg_namespace n
    JOIN pg_class c ON n.oid = c.relnamespace
    JOIN information_schema.role_table_grants ac ON c.relname = ac.table_name AND n.nspname = ac.table_schema
    RIGHT JOIN pg_roles p ON ac.grantee = p.rolname
  WHERE
    n.nspname = '<your_schema_name>'
  UNION ALL
  SELECT
    n.nspname AS schema_name,
    p.proname AS object_name,
    'f' AS object_type,
    r.rolname AS role_name,
    COALESCE(a.privilege_type, '') AS privilege
  FROM
    pg_namespace n
    JOIN pg_proc p ON n.oid = p.pronamespace
    JOIN information_schema.routine_privileges a ON p.proname = a.routine_name AND n.nspname = a.routine_schema
    RIGHT JOIN pg_roles r ON a.grantee = r.rolname
  WHERE
    n.nspname = '<your_schema_name>'
)
SELECT
  rp1.schema_name,
  rp1.object_name,
  CASE rp1.object_type
    WHEN 'r' THEN 'TABLE'
    WHEN 'v' THEN 'VIEW'
    WHEN 'S' THEN 'SEQUENCE'
    WHEN 'f' THEN 'FUNCTION'
    ELSE 'UNKNOWN'
  END AS object_type,
  rp1.role_name AS role1,
  rp1.privilege AS role1_privilege,
  rp2.role_name AS role2,
  rp2.privilege AS role2_privilege
FROM
  role_permissions rp1
  FULL OUTER JOIN role_permissions rp2 ON rp1.schema_name = rp2.schema_name
    AND rp1.object_name = rp2.object_name
    AND rp1.object_type = rp2.object_type
    AND rp2.role_name = '<role2_name>'
WHERE
  rp1.role_name = '<role1_name>'
  OR rp2.role_name = '<role2_name>'
ORDER BY
  rp1.schema_name, rp1.object_name, rp1.object_type;

Version 2

WITH role_permissions AS (
    SELECT
        nspname AS schema_name,
        relname AS object_name,
        CASE
            WHEN relkind = 'r' THEN 'table'
            WHEN relkind = 'v' THEN 'view'
            WHEN relkind = 'S' THEN 'sequence'
            ELSE 'unknown'
        END AS object_type,
        grantee,
        privilege_type
    FROM
        pg_namespace n
        JOIN pg_class c ON n.oid = c.relnamespace
        JOIN information_schema.role_table_grants g ON g.table_schema = n.nspname AND g.table_name = c.relname
    WHERE
        n.nspname = 'your_schema_name'
        AND grantee IN ('role1', 'role2')
    UNION ALL
    SELECT
        nspname AS schema_name,
        proname AS object_name,
        'function' AS object_type,
        grantee,
        privilege_type
    FROM
        pg_namespace n
        JOIN pg_proc p ON n.oid = p.pronamespace
        JOIN information_schema.role_routine_grants g ON g.routine_schema = n.nspname AND g.routine_name = p.proname
    WHERE
        n.nspname = 'your_schema_name'
        AND grantee IN ('role1', 'role2')
)
SELECT
    rp1.schema_name,
    rp1.object_name,
    rp1.object_type,
    rp1.privilege_type AS role1_privilege,
    rp2.privilege_type AS role2_privilege
FROM
    role_permissions rp1
    LEFT JOIN role_permissions rp2
        ON rp1.schema_name = rp2.schema_name
        AND rp1.object_name = rp2.object_name
        AND rp1.object_type = rp2.object_type
        AND rp2.grantee = 'role2'
WHERE
    rp1.grantee = 'role1'
    AND (rp1.privilege_type IS DISTINCT FROM rp2.privilege_type OR rp2.privilege_type IS NULL)
ORDER BY
    rp1.schema_name,
    rp1.object_name,
    rp1.object_type;

Version 3

WITH role_permissions AS (
    -- Subquery for Role 1 permissions
    SELECT
        'table' AS object_type,
        table_name,
        'SELECT' AS permission,
        grantee AS role_name,
        privilege_type AS permission_granted
    FROM
        information_schema.role_table_grants
    WHERE
        table_schema = 'your_schema' AND grantee = 'role1'
    
    UNION ALL
    
    -- Subquery for Role 2 permissions
    SELECT
        'table',
        table_name,
        'SELECT',
        grantee AS role_name,
        privilege_type
    FROM
        information_schema.role_table_grants
    WHERE
        table_schema = 'your_schema' AND grantee = 'role2'
),
-- Compare permissions between roles
comparison AS (
    SELECT
        object_type,
        table_name,
        permission,
        COALESCE(role1.permission_granted, 'NULL') AS role1_permissions,
        COALESCE(role2.permission_granted, 'NULL') AS role2_permissions
    FROM
        (SELECT DISTINCT ON (table_name) * FROM role_permissions WHERE role_name = 'role1') AS role1
    FULL OUTER JOIN
        (SELECT DISTINCT ON (table_name) * FROM role_permissions WHERE role_name = 'role2') AS role2
    USING (object_type, table_name, permission)
)
SELECT * FROM comparison;

Version 4

WITH object_permissions AS (
  SELECT
    'table' AS object_type,
    table_schema,
    table_name,
    grantee,
    privilege_type
  FROM information_schema.table_privileges
  UNION ALL
  SELECT
    'function' AS object_type,
    routine_schema,
    routine_name,
    grantee,
    privilege_type
  FROM information_schema.routine_privileges
  UNION ALL
  SELECT
    'view' AS object_type,
    table_schema,
    table_name,
    grantee,
    privilege_type
  FROM information_schema.view_privileges
  UNION ALL
  SELECT
    'sequence' AS object_type,
    nspname AS table_schema,
    relname AS table_name,
    grantee,
    'USAGE' AS privilege_type -- Simplified for sequences, adjust as needed
  FROM pg_catalog.pg_sequence
  JOIN pg_catalog.pg_namespace ON pg_sequence.seqnamespace = pg_namespace.oid
)
SELECT
  op1.object_type,
  op1.table_schema,
  op1.table_name,
  op1.privilege_type AS role1_permission,
  op2.privilege_type AS role2_permission
FROM object_permissions op1
FULL OUTER JOIN object_permissions op2
  ON op1.object_type = op2.object_type
  AND op1.table_schema = op2.table_schema
  AND op1.table_name = op2.table_name
  AND op1.grantee = 'role1'
  AND op2.grantee = 'role2'
WHERE op1.table_schema = 'your_schema'
  AND (op1.grantee IS NOT NULL OR op2.grantee IS NOT NULL);