学习笔记之--047.第二章 限制和排序数据

语法:select * |{[DISTINCT] column | expression [alias],...} FROM table [WHERE condition(s)];

select employee_id,last_name,job_id,department_id from employees where department_id=90;

=

>

>=

<

<=

<>

BETWEEN...AND...

IN(set)

like

is null

select last_name,salary from employees where salary <=3000;

select last_name,salary from employees where salary salary BETWEEN 2000 AND 3500;

select employee_id,last_name,salary,manager_id from employees where manager_id IN (100,102,201);

select first_name from employees where first_name like ‘_S%‘;

%匹配符   _匹配符

逻辑运算

and     or     not

排序

ORDER BY  默认升序,只影响前当前字段.

ASC  升序

DESC 降序