create database myIndexDemo
go
use myIndexDemo
go
create table ABC
(
A int not null,
B char(10),
C varchar(10)
)
go
insert into ABC
select 1,’B’,’C’
union
select 5,’B’,’C’
union
select 7,’B’,’C’
union
select 9,’B’,’C’
go
select * from ABC
–在ABC表上创建聚集索引
create clustered index CLU_ABC
on ABC(A)
GO
–查看索引
sp_helpIndex ABC
–插入数据
insert into ABC
values(2,’B’,’C’)
–因为有聚集索引所以整个表的物理结构发生了变化
–此时按照该索引查询的内容为:
select * from ABC WITH(index = CLU_ABC) WHERE A>1 AND A<5
–删除索引后
Drop index ABC.CLU_ABC
–查询内容物理顺序还是按照顺序的
select * from ABC
–在ABC表上创建非聚集索引
create nonclustered index NONCLU_ABC
on ABC(A)
–查看索引
sp_helpIndex abc
–插入数据
insert into ABC
values(4,’B’,’C’)
–因为有聚集索引所以整个表的物理结构发生了变化
–此时查询的内容为:
select * from ABC WITH(index = NONCLU_ABC)
–删除索引后
Drop index ABC.NONCLU_ABC
–查询内容物理顺序是按照插入的顺序
select * from ABC
