Re: [SQL] CASE WHEN / 6.4.2? + no doc in installed documentation

"Emils Klotins" <emils(at)mail(dot)usis(dot)bkc(dot)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