自定义函数:获得整型包含行的数量的结果集2

drop table if exists t2;    create table t2    (      s1 int, primary key (s1)      )    engine=innodb;  delete from t2;insert into t2(s1) values(22),(54),(15),(69);select * from t2;drop function if exists running_total;delimiter // create function running_total(adder int)   -- 写成in adder int报错,诡异returns int begin   set @running_total = @running_total + adder;   return @running_total;  end;  //     delimiter ;set @running_total=0;select running_total(s1), s1 from t order by s1;/*+-------------------+------+| running_total(s1) | s1   |+-------------------+------+|                 4 |    4 ||                 9 |    5 ||                15 |    6 |+-------------------+------+*/