Unflattened CASE statements in ELSE clause SQL-L058
Anti-pattern
Minor
Nested CASE statement in ELSE clause could be flattened.
Bad practice
In this example, the outer CASE’s ELSE is an unnecessary, nested CASE.
SELECT
CASE
WHEN species = 'Cat' THEN 'Meow'
ELSE
CASE
WHEN species = 'Dog' THEN 'Woof'
END
END as sound
FROM mytable
Recommended
SELECT
CASE
WHEN species = 'Cat' THEN 'Meow'
WHEN species = 'Dog' THEN 'Woof'
END AS sound
FROM mytable