The ELSE branch

Provide a default with ELSE.

ELSE branch

ELSE provides a default result when no WHEN condition matches. Without ELSE, NULL is returned.

SELECT name,
  CASE WHEN stock = 0 THEN 'tükendi'
       ELSE 'stokta' END AS status
FROM products;

This query tags out-of-stock products.

name, CASE WHEN stock = 0 THEN 'tükendi' ELSE 'stokta' END … is selected from products.

Without ELSE, if no WHEN matches, CASE returns NULL. This can lead to unexpected results.

For example, if you leave out ELSE 'stokta', products whose stock status is unknown show up empty in the report.

Write CASE WHEN stock = 0 THEN 'tükendi' ELSE 'stokta' END to mark out-of-stock items.

Show example solution

SELECT name,
  CASE WHEN stock = 0 THEN 'tükendi'
       ELSE 'stokta' END AS status
FROM products;

Add ELSE

CASE WHEN stock = 0 THEN 'tükendi' ____ 'stokta' END

Show answer

CASE WHEN stock = 0 THEN 'tükendi' ELSE 'stokta' END