开发工具与关键技术:Oracle sql*plus PLSQL Developer
作者:杨春桃 撰写时间:2019-04-07
撰写时间:2019年04月07日
其它比较运算符:
操作符 | 含义 |
---|---|
Between…and… | 在两个值之间(包含边界) |
In(set) | 等于值列表中的一个 |
like | 模糊查询 |
Is null | 空值 |
Between…and…显示在一个区间内的值(左边放小值,右边放大值)
Select last_name,salary from employees where salary between 3000 and 6000;
还可以这样写:
Select last_name,salary from employees where salary>=3000 and salary<=6000;
In :显示列表中的值(in里面的值可以有不成立的)
Select last_name,salary,department_id
From employees
Where department_id in(30,40,50)
还可以这样:
Select last_name,salary,department_id
From employees
Where department_id=30 or department_id=40 or department_id=55
Like:选择类似的值(模糊查询)
Select first_name from employees where first_name like ‘S%’
ECSAPE:转义字符
Select job_id from employees where job_id like ‘IT_%’ escape ‘\’
Is null:空值(查找出空值)
Select last_name,commission_pct
From employees
Where commission_pct is null
Is not null 有值(查找出有值的)
Select last_name,commission_pct
From employees
Where commission_pct is not null