set global log_bin_trust_function_creators = 1;
delimiter //
drop function f_test//
create function f_test()
returns varchar(100)
begin
declare gz DOUBLE(11,2);
declare g1 DOUBLE(11,2);
declare g2 DOUBLE(11,2);
declare content varchar(100);
set g1=5;
set g2=6;
set content=concat('',g1,'*5+',g2,'');
select content into gz;
return gz;
end//
delimiter ;