A subquery in theFROMclause of aSELECTstatement is called an inline view which has the following syntax: SELECT*FROM(subquery) [AS] inline_view;Code language:SQL (Structured Query Language)(sql) For example, the following statement returns the top 10 orders with the highest values: SELECTorder...
select mp.prd_id,mp.prd_type_id,mp.name from more_products mp; ---查询出被购买㢧的产品,并且价格低于20元的产品id select p.product_id from products p where p.price<20 intersect select distinct pr.product_id from purchases pr; --多表查询 select distinct p.product_id from products p,p...
SQL> select count(*) from so_handle; COUNT(*) --- 1296263 select count(*) from ctrl_asgn where CTRL_ASGN.STATE = 'B' AND CTRL_ASGN.STS = 'D'; COUNT(*) --- 331490 select count(*) from so where SO.STATE= 'B' AND SO.HALT ='N'; COUNT(*) --- 361 select count(*) from...
我编写了实际的select语句,它自己工作,脚本如下: SELECT job_id FROM JOBS WHERE job_id IN ('AD_CMMS') 当我试图将insert into语句与select语句合并时出现问题,下面是包含select语句的完整脚本: INSERT INTO Employees VALUES (242, 'Anouar', 'seljouki', 'seljouki84@gmail.com', '0662777081', date19...
SELECT 语句中的子查询子查询(Sub Query)或者说内查询(Inner Query),也可以称作嵌套查询(Nested Query),是一种嵌套在其他 SQL 查询的 WHERE 子句中的查询...使用子查询必须遵循以下几个规则: 子查询必须括在圆括号中。 子查询的 SELECT 子句中只能有一个列,除.
■ A subquery in a DELETE, SELECT, or UPDATE statement ■ A query of a view or of a materialized view ■ A SELECT statement with the DISTINCT operator ■ A SELECT statement with a GROUP BY clause or ORDER BY clause ■ A SELECT statement that is combined with another SELECT statement wit...
SQL> select * from employees where department_id in (10,20,30); 1. 他的执行计划,可以看到INLIST ITERATOR,通过谓词,IN确实用OR进行改写,这两者是等价的, SQL> select * from table(dbms_xplan.display_cursor(null,null,'advanced')); --- | Id | Operation | Name | Rows | Bytes | Cost (%...
IN与EXISTS有一点要记住:IN一般是用于非相关子查询,而EXISTS一般用于相关子查询。当然IN也可以用于相关子查询,EXISTS也可以用于非相关子查询。但是这区别很重要,虽然优化器很强大,但是查询转换是有一定的限制的,在EXISTS性能低下,无法进行相关查询转换,比如不能UNNEST SUBQUERY,那么可能我们需要改写SQL,通常可以用IN/...
The subquery finds all the category_id values where COUNT is 1. We don’t need to have COUNT in the SELECT part of the subquery, however, if we do, the query will display an error. The UPDATE statement will update the price where the category meets the criteria of the subquery. ...
WITHsubquery_nameAS(the aggregation SQL statement)SELECT(query naming subquery_name); With查询语句不是以select开始的,而是以“WITH”关键字开头。 可认为在真正进行查询之前预先构造了一个临时表TT,之后便可多次使用它做进一步的分析和处理 优点 使用SQL with 子句的优点, ...