如何通过从基表中选择一定范围内的值来创建 MySQL 视图?
mysqlmysqli database更新于 2024/2/27 2:01:00
众所周知，MySQL BETWEEN 运算符可用于从一定范围内的值中选择值。我们可以使用 BETWEEN 运算符和视图从基表中选择一定范围内的值。为了理解这个概念，我们使用基表"student_info"，其中包含以下数据 −
mysql> Select * from Student_info; +------+---------+------------+------------+ | id | Name | Address | Subject | +------+---------+------------+------------+ | 101 | YashPal | Amritsar | History | | 105 | Gaurav | Chandigarh | Literature | | 125 | Raman | Shimla | Computers | | 130 | Ram | Jhansi | Computers | | 132 | Shyam | Chandigarh | Economics | | 133 | Mohan | Delhi | Computers | +------+---------+------------+------------+ 6 rows in set (0.00 sec)
示例
以下查询将创建一个名为‘Info’的视图，使用‘BETWEEN’运算符选择特定范围内的某些值 −
mysql> Create or Replace view Info AS SELECT * from student_info WHERE Name BETWEEN 'C' AND 'P'; Query OK, 0 rows affected (0.14 sec) mysql> Select * from info; +------+--------+------------+------------+ | id | Name | Address | Subject | +------+--------+------------+------------+ | 105 | Gaurav | Chandigarh | Literature | | 133 | Mohan | Delhi | Computers | +------+--------+------------+------------+ 2 rows in set (0.00 sec)
类似地，我们可以使用 NOT 与 BETWEEN 运算符来选择与查询中写入的值不同的范围 −
mysql> Create or Replace view Info AS SELECT * from student_info WHERE Name NOT BETWEEN 'C' AND 'P'; Query OK, 0 rows affected (0.06 sec) mysql> Select * from Info; +------+---------+------------+-----------+ | id | Name | Address | Subject | +------+---------+------------+-----------+ | 101 | YashPal | Amritsar | History | | 125 | Raman | Shimla | Computers | | 130 | Ram | Jhansi | Computers | | 132 | Shyam | Chandigarh | Economics | +------+---------+------------+-----------+ 4 rows in set (0.00 sec)
