----创建表 if OBJECT_ID(N'IndexTable',N'U') is not null drop table IndexTable go create table IndexTable ( ID int identity(1,1) primary key not null, aaa varchar(8) ) goinsert into IndexTable select 'afffff'----创建字段aaa的索引 CREATE UNIQUE INDEX In_aaa ON IndexTable (aaa)
----创建表
if OBJECT_ID(N'IndexTable',N'U') is not null drop table IndexTable
go
create table IndexTable
(
ID int identity(1,1) primary key not null,
aaa varchar(8)
)
goinsert into IndexTable
select 'afffff'----创建字段aaa的索引
CREATE UNIQUE INDEX In_aaa
ON IndexTable (aaa)
2.在这个计算列上建索引
可以考虑,但必须保证这个公式的参数有效,也就是 aaa 字段的长度必须不小于4.