由于表变量定义完毕以后,不支持对表变量结构的任何变更和索引创建,所以很多人会认为表变量不能创建索引,比如这篇文章SQL Server Temp Table vs Table Variable Performance Testing中的这句话“However, when we query rows using the indexed column of the temporary table, which is not indexed in the table va...
-- Table creation logicCREATETABLE#temptable ([col1] [int]NOTNULLprimary key,[col2] [int]NULL, [col3] [int]NULL,[col4] [varchar](50)NULL)DECLARE@tablevariableTABLE([col1] [int]NOTNULLprimary key,[col2] [int]NULL, [col3] [int]NULL,[col4] [varchar](50)NULL,indexIX_col2(col...
AlterTable#1AddConstraintCK_#1_NrCheck(NrBetween'10001'And'19999') Go < 脚本S1.>中,可以看出在临时表#1的创建时,创建Constraint如“Constraint PK_#1_ID Primary Key(ID)”,也可以在创建临时表#1后创建Constraint,如“Alter Table #1 Add Constraint CK_#1_Nr Check(Nr Between '10001' And'19999')”,...
我们很多程序员认为临时表非常危险,因为临时表有可能被多个连接所共享.其实在SQL Server中存在两种临时表:局部临时表和全局临时表,局部临时表(Local temp table)以#前缀来标识,并且只能被创建它的连接所使用.全局临时表(Global temp table)以##前缀来进行标识,并且可以和其它连接所共享. 局部临时表 局部临时表不能够...
Temp tables may be a better solution in this case. For queries that join the table variable with other tables, use the RECOMPILE hint, which causes the optimizer to use the correct cardinality for the table variable. table variables aren't supported in the SQL Server optimizer's cost-based...
Scenarios where temp table/variable are not cached (see below) may cause performance degradation as compared to SQLServer2000. Following are scenarios where temp table/variable are not cached: 1. select into #t 2. alter table #t 3. create index...
C. Scenario: Replace session tempdb #table D. Scenario: Table variable can be MEMORY_OPTIMIZED=ON Show 4 more Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance If you use temporary tables, table variables, or table-valued parameters, consider conversions of them to levera...
其实在SQL Server中存在两种临时表:局部临时表和全局临时表,局部临时表(Local temp table)以#前缀来标识,并且只能被创建它的连接所使用.全局临时表(Global temp table)以##前缀来进行标识,并且可以和其它连接所共享.局部临时表局部临时表不能够被其它连接所共享的原因其实是在SQL Server 2000中自动为局部临时表的表...
In SQL Server 2000, a table variable can’t be the destination of a SELECT INTO statement or a INSERT EXEC (now fixed); You can’t call user-defined functions from CHECK constraints, DEFAULT values, and computed columns in the table variable. The only constraints that you’re allowed ...
table_name Nom de la table de destination lors de l’importation de données dans SQL Server (in) ou nom de la table source lors de l’exportation de données à partir de SQL Server (out). view_name Nom de la vue de destination lors de la copie de données vers SQL Server (in) ...