SQL 必知必会笔记9使用子查询
- WBOYOriginal
- 2016-06-07 17:39:30962browse
子查询（subquery），即嵌套在其他查询中的查询。 1. 利用子查询进行过滤 SELECT 语句中，子查询总是从内向外处理。示例: 1 SELECT cust_name, cust_contact 2 FROM Customers 3 WHERE cust_id IN ( SELECT cust_id order_num IN ( SELECT order_num 6 FROM
子查询（subquery），即嵌套在其他查询中的查询。
1. 利用子查询进行过滤SELECT 语句中，，子查询总是从内向外处理。示例:
1 SELECT cust_name, cust_contact 2 FROM Customers 3 WHERE cust_id IN (SELECT cust_id order_num IN (SELECT order_num 6 FROM OrderItems ));
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