Nickname or name as a fallback

Question

Accepted Answer

COALESCE returns the first non-NULL argument. For Alice, nickname is 'Ace' (not NULL) so it returns 'Ace'. For Bob, nickname is NULL so it falls through to name, returning 'Bob'. COALESCE is the standard way to substitute a fallback value when a column might be NULL.

id	name	nickname
1	Alice	Ace
2	Bob	NULL