if判断

delimiter //
CREATE PROCEDURE proc_if ()
BEGIN

        declare i int default 0;
        if i = 1 THEN
                SELECT 1;
        ELSEIF i = 2 THEN
                SELECT 2;
        ELSE
                SELECT 7;
        END IF;

END //
delimiter ;

while循环

delimiter //
create proceduer proc_while() 
begin

        declare num int ;
        set num = 0 ;
        while num < 10 do
                select
                        num ;
                set num = num + 1 ;
        end while ;

end //
delimiter ;