Re: PL/pgSQL 2

2014-09-03 21:01 GMT+02:00 David G Johnston <david(dot)g(dot)johnston(at)gmail(dot)com>:

> This is more of an SQL request the pl/pgsql but is/has there been thought
> to
> adding the ternary if/then opeator? Something like:
>
> boolean_exp ?> val_if_true : val_if_false
>
> using "?" by itself would be OK but not ideal - and the addition of the ">"
> doesn't seem hateful...
>
> Sorry if this is deemed off-topic but I just went to write
>
> CASE WHEN boolean_exp THEN val_if_true ELSE val_if_false END
>
> And the fact there is as much standard code as there is custom bothered me
> just as is being discussed on this thread.
>
> I'm going to go write a "ifthen(bool, anyelement, anyelement)" function
> now....
>
>
if you use a SQL (SQL macro, then it can be effective)

postgres=# CREATE OR REPLACE FUNCTION if(bool, anyelement, anyelement)
RETURNS anyelement AS $$SELECT CASE WHEN $1 THEN $2 ELSE $3 END $$ LANGUAGE
sql;
CREATE FUNCTION
postgres=# CREATE OR REPLACE FUNCTION fx(text) RETURNS text AS $$ BEGIN
RAISE NOTICE '%', $1; RETURN $1; END$$ LANGUAGE plpgsql;
CREATE FUNCTION
postgres=# SELECT if(false, fx('msg1'), fx('msg2'));
NOTICE: msg2
if
------
msg2
(1 row)

postgres=# SELECT if(true, fx('msg1'), fx('msg2'));
NOTICE: msg1
if
------
msg1
(1 row)

Only necessary parameters are evaluated

Pavel

> David J.
>
>
>
>
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