3. 如果CTE的表达式名称与某个数据表或视图重名,则紧跟在该CTE后面的SQL语句使用的仍然是CTE,当然,后面的SQL语句使用的就是数据表或视图了,如下面的SQL语句所示: -- table1是一个实际存在的表 with table1 as ( select * from persons where age < 30 ) select * from table1 -- 使用了名为
YouTube – SQL WITH Clause | How to write SQL Queries using WITH Clause | SQL CTE (Common Table Expression) 特色 1. CTE 可以引用自身, 实现递归查询. (Oracle 用 connect by prior) 2. 它有点像表变量, 其后的 query 都可以引用它. 然后自动销毁. 很方便 3. 可读性很棒 复用与可读性优化 来看...
Warehouse in Microsoft Fabric SQL database in Microsoft Fabric Specifies a temporary named result set, known as a common table expression (CTE). This is derived from a simple query and defined within the execution scope of a single SELECT, INSERT, UPDATE, DELETE, or MERGE statement. This clau...
syntaxsql复制 [WITH<common_table_expression>[ ,...n ] ]<common_table_expression>::=expression_name[ (column_name[ ,...n ] ) ]AS(CTE_query_definition) 参数 expression_name 公用表表达式的有效标识符。 expression_name 须不同于在同一WITH <common_table_expression>子句中定义的任何其他公用表表达...
What is a SQL CTE or Common Table Expression in SQL Server? A SQL CTE (Common Table Expression) defines a temporary result set which you can then use in a SELECT statement. It becomes a convenient way to manage complicated queries.
BuiltInFunctionTableReference BulkInsertBase BulkInsertOption BulkInsertOptionKind BulkInsertStatement BulkOpenRowset CallTarget CaseExpression CastCall CatalogCollation CatalogCollationOption CellsPerObjectSpatialIndexOption CertificateCreateLoginSource CertificateOption CertificateOptionKinds CertificateStatementBas...
CTE复用的第一步是在QueryPlan中发现SQL里CTE并表示其数据结构。在上图类似的数据库架构中,Parser/Optimizer基础功能就是用Meta描述SQL对应的执行计划,主要有几个方面: 1. 算子输出列顺序,类型和各层如何对齐2. 各个算子对应的物理实现算法3. 整个执行计划的拓扑结构(数据怎么传输,拓扑网络该怎么连边) 为了识别和...
CommonTableExpression 类 CommonTableExpression 构造函数 CommonTableExpression 方法 CommonTableExpression 属性 CompositeGroupingSpecification 类 CompressionEndpointProtocolOption 类 CompressionPartitionRange 类 ComputeClause 类 ComputeFunction 类 ComputeFunctionType 枚举 ConstraintDefinition 类 ConstraintEnforcement 枚举 ...
Transact-SQL 语法约定 语法 复制 [ WITH <common_table_expression> [ ,...n ] ] <common_table_expression>::= expression_name [ ( column_name [ ,...n ] ) ] AS ( CTE_query_definition ) 参数 expression_name 公用表表达式的有效标识符。expression_name必须与在同一 WITH <common_table_expressi...
MISC === Slides 40-59 of http://fr.slideshare.net/MarkusWinand/modern-sql In SQL2011 it is optional feature T131/132 described in paragraph . It is possible to emulate this with a generic SP: http://guilhembichot.blogspot.co.uk/2013/11/with-recursive-and-mysql.html but this SP has...