统计sql语句

drop table if exists testGroup;

create table testGroup(id int,goods_name varchar(50),num int,bill_type int);
insert into testGroup(id,goods_name,num,bill_type) values(1,"商品1",11,2);
insert into testGroup(id,goods_name,num,bill_type) values(1,"商品1",100,1);
insert into testGroup(id,goods_name,num,bill_type) values(2,"商品2",33,1);
insert into testGroup(id,goods_name,num,bill_type) values(2,"商品2",44,1);
insert into testGroup(id,goods_name,num,bill_type) values(5,"商品5",66,1);

select * from testGroup;
select sum(t.num),t.id,t.goods_name from testGroup t group by t.id
select sum(case bill_type when 1 then t.num when 2 then  -t.num end  ) as totalNum,t.id,t.goods_name from testGroup t group by t.id