|
use master
go
if exists(select 1 from sysdatabases where name =‘MyGroupDB‘)
ALTER DATABASE MyGroupDB SET SINGLE_USER with ROLLBACK IMMEDIATE
drop database MyGroupDB
go
create database MyGroupDB
go
use MyGroupDB
go
create Table Category
(
Category_ID int identity(1,1),
Category_Name varchar(100)
)
go
create Table Product
(
Product_ID int identity(1,1),
CategoryID int ,
Product_Name varchar(100)
)
go
insert into Category values(‘手机‘)
insert into Category values(‘台式机‘)
insert into Category values(‘数码相机‘)
go
insert into Product values(1,‘诺基亚‘)
insert into Product values(1,‘三星‘)
insert into Product values(1,‘苹果‘)
insert into Product values(2,‘HP‘)
insert into Product values(2,‘IBM‘)
insert into Product values(2,‘Dell‘)
insert into Product values(3,‘佳能‘)
insert into Product values(3,‘尼康‘)
insert into Product values(3,‘索尼‘)
go
select *
from Category
left join Product on Category_ID = CategoryID
--------------------------------------------------------
select Category_ID ,
Category_Name,
CategoryID,
Product_Name
from Category
left join Product on Category_ID = CategoryID
group by Category_ID ,CategoryID,Category_Name,Product_Name with rollup
--------------------------------------------------------
select Category_ID ,
GROUPING(Category_ID) as Category_IDGP,
Category_Name,
GROUPING(Category_Name) as Category_NameGP,
CategoryID,
GROUPING(CategoryID) as CategoryIDGP,
Product_Name,
GROUPING(Product_Name) as Product_NameGP
from Category
left join Product on Category_ID = CategoryID
group by Category_ID ,Category_Name,CategoryID,Product_Name with rollup
----------------------
select Category_ID ,
GROUPING(Category_ID) as Category_IDGP,
CategoryID,
GROUPING(CategoryID) as CategoryIDGP,
Category_Name,
GROUPING(Category_Name) as Category_NameGP,
Product_Name,
GROUPING(Product_Name) as Product_NameGP
from Category
left join Product on Category_ID = CategoryID
group by Category_ID ,Category_Name,CategoryID,Product_Name with rollup
having GROUPING(Category_ID)=0 and GROUPING(CategoryID)=0
-------------------------
select
case GROUPING(Product_Name) when 1 then Category_Name else ‘‘ end as Category_Name,
case GROUPING(Product_Name) when 0 then Product_Name else ‘‘ end as Product_Name
from Category
left join Product on Category_ID = CategoryID
group by Category_ID ,Category_Name,CategoryID,Product_Name with rollup
having GROUPING(Category_ID)=0 and GROUPING(CategoryID)=0
order by Category_ID ,Product_Name
|
今天我们用Group 和Grouping实现它，并总结一下它俩。
我们看到了好多NULL数据，而且很有规律
