Re: using case to select 'which version to use'

Rodrigo E. De León Plicet wrote:
> On Thu, Aug 20, 2009 at 10:17 AM, Gerardo Herzig<gherzig(at)fmed(dot)uba(dot)ar> wrote:
>> Hi all. I have 2 functions , which returns the same columns, but with
>> tottaly different logics. I want to wrap it with a third function, who
>> will receive a boolean argument to decide wich sub-function have to use.
>>
>> I want to use case, so i dont have to use pl/pgsql.
>>
>> This is a non-working example:
>>
>>
>> CREATE OR REPLACE FUNCTION get_oferta(varchar, varchar, varchar, bool,
>> OUT cod varchar , OUT description varchar)
>> returns setof record
>> security definer
>> as
>> $$
>> select * from case $4 when true then
>> (select * from get_oferta_from_a($1, $2, $3))
>> else
>> (select * from get_oferta_from_b($1, $2, $3))
>> end;
>> $$ language sql;
>>
>> Can i use case for a case like this?
>>
>> Thanks!
>> Gerardo
>
> Try:
>
> SELECT *
> FROM get_oferta_from_a ($1, $2, $3)
> WHERE $4
> UNION ALL
> SELECT *
> FROM get_oferta_from_b ($1, $2, $3)
> WHERE NOT $4;
>
>
Well, looks like it will work. I think i found the right syntax now:

select foo.* from
(select case $4 when false then
get_oferta_from_a($1, $2, $3)
else
get_oferta_from_b($1, $2, $3)
end) as foo;

Thanks!

Gerardo