T-SQL(Transact-SQL)是一种 SQL 扩展语言,由微软实现,运行在 Ms SQL Server 平台上。T-SQL 主要用来和SQL Server 交流,而查询语句则主要用来告诉服务器该做什么。T-SQL 是标准 SQL 语言的扩展,自然也继承了其基本功能:DDL、DML,DCL,DQL。另外,T-SQL 扩展了标准 SQL 不具备的编程特性,比如:运算符、文本
AI代码解释 SELECTp.FirstName,p.LastName,ROW_NUMBER()OVER(ORDERBYa.PostalCode)AS'Row Number',RANK()OVER(ORDERBYa.PostalCode)AS'Rank',DENSE_RANK()OVER(ORDERBYa.PostalCode)AS'Dense Rank',NTILE(4)OVER(ORDERBYa.PostalCode)AS'Quartile',s.SalesYTD,a.PostalCodeFROMSales.SalesPerson sINNERJOINPerson...
这个变量是用于执行和维护当前SQL Server实例的Windows服务名。它通常返回SQL Server默认实例MSSQLSERVER,但SQL Server的指定实例有唯一的服务名。例如在名为WoodVista的计算机上有两个SQL Server实例:默认实例和指定实例AughtEight。如在默认实例上检索@@SERVICENAME全局变量的内容,将返回MSSQLSERVER,但在指定实例上检索,...
FIRST_VALUE具有不确定性。 有关详细信息,请参阅确定性函数和不确定性函数。 示例 A. 对查询结果集使用 FIRST_VALUE 以下示例使用FIRST_VALUE返回给定产品类别中价格最低廉的产品名称。 SQL USEAdventureWorks2022; GOSELECTName, ListPrice,FIRST_VALUE(Name)OVER(ORDERBYListPriceASC)ASLeastExpensiveFROMProduction.Pr...
aggregate_function 的評估對象為此子群組上的 value_column,且其結果是作為相對應 output_column.的值來傳回。 如果子群組是空的,SQL Server 會為該 output_column 產生null 值。 如果彙總函式是 COUNT,且子群組是空的,就會傳回零 (0)。 注意 UNPIVOT 子句中的資料行識別碼會依照目錄定序。 SQL Database ...
syntaxsql复制 [FROM{} [ , ...n ] ]::={table_or_view_name[FORSYSTEM_TIME<system_time>] [ [AS]table_alias] [<tablesample_clause>] [WITH(< table_hint >[ [ , ] ...n ] ) ] |rowset_function[ [AS]table_alias] [ (bulk_column_alias[ , ...n ] ) ] |user_defined_function...
Azure SQL Database and SQL Server starting SQL Server 2017 (14.x) do support TOP WITH TIES. Aggregate function Aggregate function Not all aggregate functions are supported. For more information about supported aggregate functions in natively compiled T-SQL modules, see Supported Features for ...
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 ] ]...
SQL Server中的枢轴表。一个简单的样本 0 0 0 MMTTMM SELECT <non-pivoted column>, [first pivoted column] AS <column name>, [second pivoted column] AS <column name>, ... [last pivoted column] AS <column name>...
SQL Server figures out that the "GROUP BY" column list should be the list of columns in the input table that were not referred to explicitly by the PIVOT operator in the aggregate function or in the IN clause. So that you don't get undesired columns in the implicit GROUP BY column list...