CREATE INDEX语句所做的事情与其听上去一样-用于在指定表或视图上基于声明的列创建索引: CREATE [UNIQUE] [CLUSTERED | NONCLUSTERED] INDEX <index name> ON <table or view name>(<column name> [ASC|DESC][,...n]) INCLUDE (<column name> [,...n]) [ W
create nonclustered index idx_学生号 on tbl1(学生号) 然后再运行Script 3,部分结果如下: Table 'tbl1'. Scan count 1, logical reads 3, physical reads 0, read-ahead reads 0. Rows Executes StmtText --- 1 1 SELECT [学生姓名]=[学生姓名],[入学时间]=[入学时间] FROM [tbl1] WHERE [学生号...
但是这种查询在客服系统又经常使用,我们可以创建一个带有substr函数的基于函数的索引, create index emp_ename_substr on eemp ( substr(ename,1,2) ); 1. 这样在执行上面的查询语句时,这个基于函数的索引将排上用场,执行计划将是(INDEX RANGE SCAN)。 第十五掌 基于函数的索引要求等式匹配 上面的例子中,我们...
To create a nonclustered index by using Object Explorer In Object Explorer, expand the database that contains the table on which you want to create a nonclustered index. Expand theTablesfolder. Expand the table on which you want to create a nonclustered index. ...
CREATE TABLE [dbo].[TGongwen] ( --TGongwen是红头文件表名 [Gid] [int] IDENTITY (1, 1) NOT NULL , --本表的id号,也是主键 [title] [varchar] (80) COLLATE Chinese_PRC_CI_AS NULL , --红头文件的标题 [fariqi] [datetime] NULL , ...
SQL仅接受以下``CREATE INDEX选项用于解析目的,以帮助将现有SQL代码转换为 SQL。 这些选项不提供任何实际的功能。 CLUSTERED | NONCLUSTERED owner.catalog. ASC | DESC 下面的例子展示了这些no-op关键字的位置: CREATE UNIQUE CLUSTERED INDEX index-name ON TABLE owner.catalog.schema.table (field1 ASC, field2...
--BASIC EXAMPLE: Create a nonclustered index on a columnstore table.--Create the tableCREATETABLEt_account ( AccountKeyintNOTNULL, AccountDescriptionnvarchar(50), AccountTypenvarchar(50), UnitSoldint);--Store the table as a columnstore.CREATECLUSTERED COLUMNSTOREINDEXtaccount_cciONt_account;--Add ...
SQL Server automatically creates indexes when PRIMARY KEY and UNIQUE constraints are defined on table columns. For example, when you create a table with a UNIQUE constraint, Database Engine automatically creates a nonclustered index. If you configure a PRIMARY KEY, Database Engine automatically creat...
SQL Server automatically creates indexes when PRIMARY KEY and UNIQUE constraints are defined on table columns. For example, when you create a table with a UNIQUE constraint, Database Engine automatically creates a nonclustered index. If you configure a PRIMARY KEY, Database Engine automatically creat...
CREATE NONCLUSTERED INDEX idx_Customer_OrderDate ON Orders (CustomerID, OrderDate); 使用场景:该索引有助于加速按 CustomerID 和OrderDate 查询的性能,特别是当订单数据量较大时。 2.3. 创建单列非聚集索引 对于查询需求2,如果我们需要按 ProductID 查找所有相关订单,我们可以为 ProductID 创建单列非聚集索引。