postgres how get get multiple columns values? - postgresql

Question

CREATE OR REPLACE FUNCTION "public"."sxfun"("jcbh" text)
RETURNS "pg_catalog"."int4" AS $BODY$
declare leftplayer TEXT;
declare rightplayer TEXT;
declare leftcoin int;
BEGIN
SELECT player1 into leftplayer,player2 into rightplayer FROM table1 WHERE id=$1;
SELECT SUM(playcoin) into leftcoin FROM table2 WHERE playname=leftplayer
COMMIT;
END$BODY$
LANGUAGE plpgsql VOLATILE
COST 100
this code syntax error,let how to solve it,please

Answer 1

You are missing a return statement. In PL/pgSQL, declare starts a block, there is no need to repeat the keyword for every variable. And you can't commit in a function - and you don't need it to begin with.
As documented in the manual you need to use return to return a value from a function.
To store multiple columns into multiple variables, you need to separate them with a comma, not repeat the INTO clause.
Note that sum() returns a bigint, so your variable and return type should also be defined as bigint.
CREATE OR REPLACE FUNCTION public.sxfun(jcbh text)
RETURNS bigint
AS
$BODY$
declare
leftplayer TEXT;
rightplayer TEXT;
leftcoin bigint;
BEGIN
SELECT player1, player2
into leftplayer, rightplayer
FROM table1
WHERE id = jcbh;
SELECT SUM(playcoin)
into leftcoin
FROM table2
WHERE playname = leftplayer;
return leftcoin; --<< return the value
END
$BODY$
LANGUAGE plpgsql;
If id is a number (which the name usually indicates), the parameter jcbh should be declared as integer, not as text.
Note that you can simplify this to a single statement. There is no need for intermediate variables:
CREATE OR REPLACE FUNCTION public.sxfun(jcbh text)
RETURNS bigint
AS
$BODY$
SELECT SUM(playcoin)
FROM table2
WHERE playname IN (select leftplayer
FROM table1
WHERE id = jcbh);
$BODY$
LANGUAGE sql;