On Tue, Mar 29, 2016 at 12:38 PM, Pavel Stehule <pavel.stehule@xxxxxxxxx> wrote: > The coalesce is one few functions implemented by special rule in > PostgreSQL parser. In the SQL standard the COALESCE feature is not listed as a function; it is listed as one of the short forms of CASE expression. While it has function-like syntax, thinking of it as a function is semantically incorrect. COALESCE(a, b) is supposed to be semantically equivalent to: CASE WHEN a is not null THEN a ELSE b END Among other things, that means that this statement should not generate a divide by zero error: SELECT COALESCE(1, 1/0); -- Kevin Grittner EDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
