mysql-视图

视图是一种虚表，数据来源于其他多张或者单张表查询的内容

1.创建单表视图：

　　1.1：视图拥有该表的所有列：CREATE VIEW v1 AS SELECT * FROM t_book;

　　1.2：视图拥有该表的部分列：CREATE VIEW v2 AS SELECT bookName,price FROM t_book;

　　1.3：视图拥有该表的部分列，其列明与表的列名不相同：CREATE VIEW v3(b,p) AS SELECT bookName,price FROM t_book;

2.创建多表视图：

　　1.1：CREATE VIEW v4 AS SELECT bookName,bookTypeName FROM t_book,t_booktype WHERE t_book.bookTypeId=t_booktype.id;

3查询视图：

　　SELECT * FROM v1;

　　SELECT * FROM v2;

　　SELECT * FROM v3;