二、多行子查询(Multirow Subqueries) 多行子查询,意味着子查询返回的结果子集可以是多行。因此,我们通常用集合比较操作符(如:IN, NOT IN)把父查询和子查询连接起来。 例二: SELECTename,job,salFROMEMPWHEREdeptnoin(SELECTdeptnoFROMdeptWHEREdnameLIKE‘A%’); 三、多列子查询(Multiple-Column Subqueries): ...
A、单行子查询(Single-row subqueries)。 B、多行子查询(Multirow subqueries)。 C、内部视图型子查询(Inline views)。 D、多列子查询(Multiple-column subqueries)。 在我们继续详细讨论子查询之前,先看看写子查询的一些特别要注意的地方: A、子查询必须放在括号内。 B、子查询也必须放在比较操作符号的右边。 C...
三、 多行多列子查询 名字叫Multiple Row and Column Subqueries,使用这种语法,in中值的上限可以到10万而不是1000,足够满足绝大多数业务场景。当然,如果真的in 10万个值,性能绝对够呛,慎用… select column_X, ... from my_table where ('magic', column_X ) in ( ('magic', 1), ('magic', 2), (...
4. 使用多行多列子查询(Multiple Row and Column Subqueries) Oracle允许使用一种特殊的语法来处理超过1000个值的IN子句,这种方法通过构造一个包含多行多列的子查询来实现。但是,请注意,这种方法在性能上可能并不优于其他方法,并且当值列表非常大时,可能会导致性能问题。例如: sql SELECT column_X, ... FROM ...
1、单行子查询(=) single-row subqueries 解释:单行子查询是指返回一行数据的子查询语句 2、多行子查询(in) multiple-row subqueries 解释:多行子查询是指返回多行数据的子查询 3、多行子查询使用all操作符 Select ename,sal,deptno from emp where sal>all(select sal from emp where deptno =30); ...
##23 Q24. Which two statements are true regarding multiple-row subqueries? (Choose two.) A. They can contain group functions. B. They always contain a subquery within a subquery. C. They use the < ALL operator to imply less than the maximum. D. They can be used to retrieve multiple...
The optional XML keyword generates XML output for the query.The XML keyword permits the pivot_in_clause to containeither a subquery or the wildcard keyword ANY. Subqueriesand ANY wildcards are useful whenthe pivot_in_clause values are not known in advance. With XML output,the values of the...
Multi Row Subqueries Explains what a multi row subquery is and what it can be used for 10. Inserting, Updating, and Deleting Data Inserting Data How to add or insert data into a table Related:The Complete Guide to the SQL INSERT INTO Statement ...
The optional XML keyword generates XML output for the query.The XML keyword permits the pivot_in_clause to containeither a subquery or the wildcard keyword ANY. Subqueriesand ANY wildcards are useful whenthe pivot_in_clause values are not known in advance. With XML output,the values of the...
-- Single row -- select v1 from t1 where id = 1000; select v1 from t1 where id = 2000; -- -- multiple rows: 5, 50, 500, 1500 -- select max(v1) from t1 where id between 11 and 15; select max(v1) from t1 where id between 101 and 150; select max(v1) from t1 where...