CREATE COLUMNSTORE INDEX Transact-SQL 语法约定 语法 适用于 SQL Server、Azure SQL 数据库和 Azure SQL 托管实例的语法 syntaxsql 复制 CREATE [ UNIQUE ] [ CLUSTERED | NONCLUSTERED ] INDEX index_name ON ( column [ ASC | DESC ] [ ,...n ] ) [ INCLUDE ( column_name [ ,...n ] ) ] ...
CREATE UNIQUE CLUSTERED INDEX IndexPOView ON POView (PurchaseOrderID) GO 你可以对比一下查询语句与查询索引视图的执行计划,索引视图的方式提供了更好的查询性能: SQL Server 的查询优化器总是尝试找到最佳的执行计划,有时候虽然你建立了索引视图,但优化器依然使用了原始表上的索引,此时你可以使用 WITH NOEXPAND ...
由于SQL Server不直接访问磁盘,每个操作都需要先把数据从磁盘加载到内存中,内存的容量相对磁盘来说又比较小,一旦索引很大,查询过程造成的内存压力也会随 之而来,对数据缓存和计划缓存都有不可忽视的影响。对聚集索引的维护,比如重建,会引发非聚集索引的连带效应。索引越多速度越慢。很多系统并没有充足的时 间让你任...
由於SQL Server 查詢最佳化工具通常會選取最好的查詢執行計畫,因此我們建議只有資深的開發人員和資料庫管理員才應該使用提示,並將其當作最後的解決辦法。 適用範圍: DELETE INSERT SELECT UPDATE MERGE Transact-SQL 語法慣例 語法 syntaxsql 複製 WITH ( [ [ , ] ...n ] ) ::= { NOEXPAND | INDEX ( ...
syntaxsql 複製 CREATE [ OR ALTER ] FUNCTION [ schema_name. ] function_name ( [ { @parameter_name [ AS ] [ type_schema_name. ] parameter_data_type [ NULL ] [ = default ] [ READONLY ] } [ , ...n ] ] ) RETURNS return_data_type [ WITH <function_option> [ , ...n ] ]...
Note that the keyword NONCLUSTERED is optional in this example. Also note that the syntax for memory-optimized nonclustered indexes is similar to the traditional disk-based nonclustered indexes. The only difference is that with memory-optimized indexes you need to ...
Syntax for SQL Server, Azure SQL Database, Azure SQL Managed Instance syntaxsql Copy CREATE [ UNIQUE ] [ CLUSTERED | NONCLUSTERED ] INDEX index_name ON ( column [ ASC | DESC ] [ ,...n ] ) [ INCLUDE ( column_name [ ,...n ] ) ] [ WHERE <filter_predicate> ] [ WITH ( <...
syntaxsql 复制 CREATE [ OR ALTER ] FUNCTION [ schema_name. ] function_name ( [ { @parameter_name [ AS ] [ type_schema_name. ] parameter_data_type [ NULL ] [ = default ] [ READONLY ] } [ , ...n ] ] ) RETURNS return_data_type [ WITH <function_option> [ , ...n ] ]...
Syntax for SQL Server, Azure SQL Database, Azure SQL Managed Instance syntaxsql Copy CREATE [ UNIQUE ] [ CLUSTERED | NONCLUSTERED ] INDEX index_name ON ( column [ ASC | DESC ] [ ,...n ] ) [ INCLUDE ( column_name [ ,...n ] ) ] [ WHERE <filter_predicate> ] [ WITH ( <...
CREATE CLUSTERED INDEX ci_TestTable ON TestTable (col1); GO -- Populate the table. INSERT INTO TestTable VALUES (1); GO 示例A会话1:在一个事务中执行一个 SELECT 语句。 由于 HOLDLOCK 锁提示,此语句将获取并保留一个对此表的意向共享锁(IS 锁)(此例中忽略行锁和页锁)。 IS 锁只能在分配给事务...