你可以通过SqlServer Management Studio的UI界面操作来指定计算列,也可以通过Transact-SQL来指定计算列。 在Sql Server Management Studio中, 右键列 -》modify -》 新建列 -》Computed Column Specification 中来指定计算列。 通过Transact-SQL 来指定计算列,格式为:列名as表达式。 --在创建表的时候指定为计算列create...
IFEXISTS(SELECT*FROMsys.tablesWHEREname='computed_column_test_computed')BEGINDROPTABLEdbo.computed_column_test_computedENDIFEXISTS(SELECT*FROMsys.tablesWHEREname='computed_column_test_noncomputed')BEGINDROPTABLEdbo.computed_column_test_noncomputedENDCREATETABLEdbo.computed_column_test_computed ( dttmDATETIME...
A computed column expression can use data from other columns to calculate a value for the column to which it belongs. You can specify an expression for a computed column in SQL Server by using SQL Server Management Studio (SSMS) or Transact-SQL (T-SQL)....
Consider the following scenario: You use a database at compatibility level 100 in Microsoft SQL Server. You have a table in the database that contains a PERSISTED computed column. The PERSISTED computed column uses the...
(继承自 ISqlColumn。) ElementClass 获取元素的元数据类。 (继承自 IModelElement。) ExpressionDependencies 获取表达式脚本引用的对象的列表。 ExpressionScript 获取或设置用于计算列中的行值的脚本。 ExtendedProperties 获取此对象的扩展属性的列表。 (继承自 ISqlExtendedPropertyHost。) Model 获取模型引用。 (继承...
Transact-SQL 語法慣例 語法 syntaxsql複製 column_nameAScomputed_column_expression[PERSISTED[NOTNULL] ] [ [CONSTRAINTconstraint_name] {PRIMARYKEY|UNIQUE} [CLUSTERED|NONCLUSTERED] [WITHFILLFACTOR= fillfactor ] [WITH(<index_option>[, ...n ] ) ] [ON{partition_scheme_name(partition_column_name) | ...
However in some cases, you may observe that a query on computed column running on SQL 2005 instance is performing much slower as compared to the same query running on SQL 2000 instance. In this blog I will be explaining ...
SQL Server Azure SQL Database Azure SQL Managed Instance SQL database in Microsoft Fabric Specifies the properties of a computed column that is added to a table by usingALTER TABLE. Transact-SQL syntax conventions Syntax syntaxsql column_nameAScomputed_column_expression[PERSISTED[NOTNULL] ] [ [CO...
SQL Server Azure SQL 数据库 Azure SQL 托管实例 Microsoft Fabric SQL 数据库 指定使用ALTER TABLE添加到表中的计算列的属性。 Transact-SQL 语法约定 语法 syntaxsql column_nameAScomputed_column_expression[PERSISTED[NOTNULL] ] [ [CONSTRAINTconstraint_name] {PRIMARYKEY|UNIQUE} [CLUSTERED|NONCLUSTERED] [WIT...
A computed column SQL provides some limited capribilities to compute new values from data contained in the fields of the table rows, To see an example of thls,go back to SQL.View and edit the stattement to reid: SELECT ID,LastName, ...