_compute_container_sort_key.sql

WITH container_default_sort_key AS (
    SELECT * FROM (VALUES
        ('folder', 'index_asc'),
        ('album',  'index_asc'),
        ('blog',   'updated_desc')
    ) AS kv (container_type, default_sort_key)
)
SELECT COALESCE(NULLIF(NULLIF(c.sort_key, ''), 'default'), cdsk.default_sort_key) AS container_sort_key
FROM container c JOIN container_default_sort_key cdsk USING(container_type)
WHERE c.container_id = '6b6c8837-f3e5-4e63-a42b-5c07fd4b56ad';

explain_output.txt

Nested Loop  (cost=0.47..8.59 rows=1 width=42) (actual time=0.092..0.097 rows=1 loops=1)
  Join Filter: ((c.container_type)::text = cdsk.container_type)
  Rows Removed by Join Filter: 2
  Buffers: shared hit=4
  CTE container_default_sort_key
    ->  Values Scan on "*VALUES*"  (cost=0.00..0.04 rows=3 width=64) (actual time=0.003..0.005 rows=3 loops=1)
  ->  Index Scan using pk_container on container c  (cost=0.43..8.45 rows=1 width=16) (actual time=0.065..0.066 rows=1 loops=1)
        Index Cond: (container_id = '6b6c8837-f3e5-4e63-a42b-5c07fd4b56ad'::uuid)
        Buffers: shared hit=4
  ->  CTE Scan on container_default_sort_key cdsk  (cost=0.00..0.06 rows=3 width=64) (actual time=0.006..0.010 rows=3 loops=1)
Total runtime: 0.177 ms