sqlserver 聚集索引和非聚集索引實例,學習sqlserver索引的朋友可以參考下。
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表上創建聚集索引
create clustered index CLU_ABC
on ABC(A)
GO
–查看索引
sp_helpIndex ABC
–插入數據
insert into ABC
values(2,’B’,’C’)
–因為有聚集索引所以整個表的物理結構發生了變化
–此時按照該索引查詢的內容為:
select * from ABC WITH(index = CLU_ABC) WHERE A>1 AND A
–刪除索引后
Drop index ABC.CLU_ABC
–查詢內容物理順序還是按照順序的
select * from ABC
–在ABC表上創建非聚集索引
create nonclustered index NONCLU_ABC
on ABC(A)
–查看索引
sp_helpIndex abc
–插入數據
insert into ABC
values(4,’B’,’C’)
–因為有聚集索引所以整個表的物理結構發生了變化
–此時查詢的內容為:
select * from ABC WITH(index = NONCLU_ABC)
–刪除索引后
Drop index ABC.NONCLU_ABC
–查詢內容物理順序是按照插入的順序
select * from ABC
