delimiter //
drop FUNCTION if exists tests//
create FUNCTION tests() RETURNS varchar(30)
BEGIN
declare st1 VARCHAR(30) default '0';
declare st2 VARCHAR(30) default '0';
declare st3 VARCHAR(30) default '0';
declare cursor1 cursor for select address,city from persons;
FETCH next from cursor1 into st2,st3;
while @@FETCH_STATUS = 0 DO
SET st1 = CONCAT (st2,st3);
end while;
close cursor1;
RETURN st1;
END //
deallocate cursor1;
delimiter ;
#运行提示unknown system variable FETCH_STATUS
#以上是mysql语句!