delimiter |;

create procedure sp1()
begin
declare continue handler for SQLEXCEPTION begin end;
execute pstmt1;
if @a < 1
then
prepare pstmt1 from 'select 1';
set @a := 1;
else
prepare pstmt1 from 'select 2';
end if;
execute pstmt1;
end
|

delimiter ;|

set @a := 0;

call sp1();
execute pstmt1;
call sp1();
call sp1();