MariaDB - IF / ELSE IF / ELSE - kakšna je pravilna sintaksa?

Evo, imam super preprost problem.

Baza je: MariaDB 10.3.15
GUI je: DBeaver 6.1.5

Probam pa naredit IF/ELSEIF/, ki bo glede na input prebral podatke iz različne tabele. In je problem, ker je nekaj narobe s sintakso in ne najdem kaj.

Se pravi, kakšna je pravilna sintaksa?

Tole je pa primer, ki ga poženem in dobim errorje za vsak IF, ELSE IF in END IF.

USE db1;

SET @val1 = 0;

IF @val1 = 0 THEN

	SELECT * FROM db1.table1;

ELSE IF @val1 = 1 THEN

	SELECT * FROM db1.table2;

END IF;

Prva stvar je verjetno ELSEIF mora biit napisan skupaj, drugo pa verjetno napaka tudi drugje v kodi (deklariranje spremenljivk, select ki ne ve kam dati rezultate,...).

Problem rešen, potrebno je bilo dodati DELIMITER. Neki zarad podpičji.

https://mariadb.com/kb/en/library/delim...

Sample je sedaj takle (ki bo pol imel še ELSEIF in tabele ad01, ad02 , ..., ad10, ad11 itn...):

USE db1;

DELIMITER //

CREATE DEFINER=`root`@`localhost` PROCEDURE `db1`.`spCheckIfAdExists`(IN catval INT, IN subcatval INT, IN adid INT)
BEGIN
	
	IF catval = 0 THEN
	
		IF subcatval = 0 THEN
		
			#SELECT cat.id, subcat.id, ad00.id FROM db1.Category AS cat
			SELECT COUNT(*) AS 'count', IFNULL(usr.id, -1) AS 'userId'
			FROM db1.Category AS cat
			INNER JOIN db1.Subcategory AS subcat
			ON cat.id = subcat.categoryId
			INNER JOIN db1.Ad00 AS ad00
			ON subcat.id = ad00.subcategoryId
			INNER JOIN db1.Users AS usr
			ON ad00.userId = usr.id
			WHERE cat.categoryValue = catval AND subcat.subcategoryValue = subcatval AND ad00.id = adid;
		
		END IF;
	
	END IF;

END;

DELIMITER ;