dcrespo wrote:
Hi everybody,
I'm implementing something like this:
SELECT
CASE WHEN add_numbers(t1.main_number,t2.main_number)>100
THEN t1.description1
ELSE t2.description1
END AS number_description1,
CASE WHEN add_numbers(t1.main_number,t2.main_number)>100
THEN t1.description2
ELSE t2.description2
END AS number_description2
FROM table1 t1, table2 t2;
Is there a way to evaluate the 'CASE WHEN' only once?
Sure, see the implementation of CASE here:
http://www.postgresql.org/docs/8.2/static/functions-conditional.html
Not sure what you are looking for, though, since your condition in both
CASEs above is exactly the same.
--
Guy Rouillier
