WHERE [NOT] EXISTS (subquery) 在某些 Transact-SQL 语句中,子查询可以作为独立查询来计算。 从概念上说,子查询结果会代入外部查询(尽管这不一定是 SQL Server 实际处理带有子查询的 Transact-SQL 语句的方式)。 有三种基本的子查询。 它们是: 在通过 IN 或由ANY 或ALL 修改的比较运算符引入的列表...
下列範例顯示可傳回相同結果集和執行計畫的子查詢SELECT及聯結SELECT: SQL USEAdventureWorks2022; GO/* SELECT statement built using a subquery. */SELECT[Name]FROMProduction.ProductWHEREListPrice = (SELECTListPriceFROMProduction.ProductWHERE[Name] ='Chainring Bolts'); GO/* SELECT statement built using a...
/* SELECT statement built using a subquery. */ SELECT Name FROM AdventureWorks2008R2.Production.Product WHERE ListPrice = (SELECT ListPrice FROM AdventureWorks2008R2.Production.Product WHERE Name = 'Chainring Bolts' ); /* SELECT statement built using a join that returns the same result set. */...
代码:select_statement UNION [ALL] selectstatement [UNION [ALL] selectstatement][…n]其中selectstatement为待联合的SELECT查询语句。 ALL选项表示将所有行合并到结果集合中。不指定该项时,被联合查询结果集合中的重复行将只保留一行。 联合查询时,查询结果的列标题为第一个查询语句的列标题。因此,要定义列标题必须...
Select statement union | union all Select statement; 1.2.intersect交集操作 相交运算 用相交运算返回多个查询中所有的公共行。 无重复行。 原则 ?在查询中被 SELECT 语句选择的列数和数据类型必须与在查询中所使用的所有的 SELTCT 语句中的一样,但列的名字不必一样。
AlterResourceGovernorStatement AlterResourcePoolStatement AlterRoleAction AlterRoleStatement AlterRouteStatement AlterSchemaStatement AlterSearchPropertyListStatement AlterSecurityPolicyStatement AlterSequenceStatement AlterServerAuditSpecificationStatement AlterServerAuditStatement AlterServerConfigurationBufferPoolExtensionContain...
AlterResourceGovernorStatement AlterResourcePoolStatement AlterRoleAction AlterRoleStatement AlterRouteStatement AlterSchemaStatement AlterSearchPropertyListStatement AlterSecurityPolicyStatement AlterSequenceStatement AlterServerAuditSpecificationStatement AlterServerAuditStatement AlterServerConfigurationBufferPoolExtensionContainer...
AlterQueueStatement AlterRemoteServiceBindingStatement AlterResourceGovernorCommandType AlterResourceGovernorStatement AlterResourcePoolStatement AlterRoleAction AlterRoleStatement AlterRouteStatement AlterSchemaStatement AlterSearchPropertyListStatement AlterSecurityPolicyStatement AlterSequenceStatement AlterServerAuditSpecificat...
select*fromsys.objects;select*fromsys.objectswherenotobject_idin(selectnull); SeeNULL and UNKNOWN (Transact-SQL) - SQL Server | Microsoft Learn I get an empty result. This isnot expectedand thereforeincorrect. schumifrick, the empty resultis expectedand thereforecorrect,if the ...
select * from S left join using(A) union select * from S right jion T using(A); 分类: SQL 1. INSERT 通用形式: INSERT INTO tablename [colname {,colname...}] {VALUES (expr |NULL | Subquery)} 例:1. insert into orders (ordno,month) values (1107.'aug'); 2. insert into swcus...