Postgres nested if in case query
There is no IF expr THEN result ELSE result END syntax for normal SQL queries in Postgres. As there is neither an IF() function as in MySQL, you have to use CASE:
select ( case (select '1') when '1' then case when 1=1 then 0.30::float else 0.50::float end else 1.00::float end);
I don't know what you're trying to achieve with this function, but here's a working version.
CREATE FUNCTION f_test(myvalue integer) RETURNS float AS $$BEGIN IF myvalue = 1 THEN IF 1=1 THEN RETURN 0.30::FLOAT; ELSE RETURN 0.50::FLOAT; END IF; ELSE RETURN 1.0::FLOAT; END IF;END;The function returns 0.3 if input value is 1, otherwise it'll return 1. Edit: Note that 0.5 is never returned by the function.