kLfDcbJ6

1DROP FUNCTION IF EXISTS getCif;
2DELIMITER $$
3CREATE FUNCTION getCif(pSequenceNumber INT)
4    RETURNS VARCHAR(45)
5    DETERMINISTIC
6BEGIN
7	DECLARE retCif VARCHAR(45);
8	SET retCif = (SELECT cif FROM accounttbl WHERE sequence_number = pSequenceNumber);
9	RETURN (retCif);
10END $$
11DELIMITER ;
12
13drop table accounttbl;
14create table accounttbl
15(	cif varchar(45) not null,
16	sequence_number int not null
17);
18insert accounttbl values ('a',1),('b',2),('c',2);
19select getCif(1); -- ok, 'a'
20select getCif(2); -- NULL Explosion, too many values