"Emils Klotins" <emils@mail.usis.bkc.lv> writes:
> Could somebody please tell what is the correct form for either IFNULL
> or CASE SQL functions in PG?
Looking in the grammar I find:
/* Case clause* Define SQL92-style case clause.* Allow all four forms described in the standard:* - Full specification*
CASE WHEN a = b THEN c ... ELSE d END* - Implicit argument* CASE a WHEN b THEN c ... ELSE d END* - Conditional NULL*
NULLIF(x,y)* same as CASE WHEN x = y THEN NULL ELSE x END* - Conditional substitution from list, use first non-null
argument* COALESCE(a,b,...)* same as CASE WHEN a IS NOT NULL THEN a WHEN b IS NOT NULL THEN b ... END* - thomas
1998-11-09*/
I think these things will actually be documented in 6.5 :-).
BTW, there are some severe bugs in CASE in 6.4.*; it doesn't work
reliably in queries that reference more than one table. Fixed in 6.5,
as far as I know.
regards, tom lane