我们如何使用LEFT JOIN创建MySQL视图？
为了说明使用LEFTJOIN创建MySQL视图的方法，我们使用“Customers”和“Resreve”表中的以下数据-
mysql> Select * from customers; +-------------+----------+ | Customer_Id | Name | +-------------+----------+ | 1 | Rahul | | 2 | Yashpal | | 3 | Gaurav | | 4 | Virender | +-------------+----------+ 4 rows in set (0.00 sec) mysql> Select * from reserve; +------+------------+ | ID | Day | +------+------------+ | 1 | 2017-12-30 | | 2 | 2017-12-28 | | 2 | 2017-12-25 | | 1 | 2017-12-24 | | 3 | 2017-12-26 | +------+------------+ 5 rows in set (0.00 sec)
现在，下面的查询将使用上述表上的LEFTJOIN创建一个名为“customer_VLeft”的视图，该视图将具有未预订任何汽车的客户的姓名。
mysql> Create view customer_Vleft AS SELECT NAME from customers LEFT JOIN RESERVE ON customer_id = id WHERE id IS NULL; mysql> Select * from customer_Vleft; +----------+ | NAME | +----------+ | Virender | +----------+ 1 row in set (0.00 sec)