条件和排序
员工ID为90的
select * from employees e where e.department_id = 90;
员工工资小于4400的
select * from employees e where e.salary < 4400;
between…and在俩个值之间
select * from employees ewhere e.salary between 4400 and 9000;
员工工资在4400到9000之间，包含4400和9000
前面的值小，后面的值大，否则前大后小查询不到数据
部门ID为90、60的员工
select * from employees e where e.department_id in (90,60);
员工姓名g结尾的
select * from employees e where e.last_name like '%g';
员工姓名中含有i的
select * from employees e where e.last_name like '%i%';
员工姓名第二位是o的
select * from employees e where e.last_name like '_o%';
员工ID为空的员工
SELECT * FROM EMPLOYees e where e.department_id is null;
并且 和 and 或者 or
工资一万以上并且工作名称含有MAN字符的员工
select * from employees e where e.salary > 10000 and e.job_id like '%MAN%';
工资一万以上或者工作名称含有MAN字符的员工
select * from employees e where e.salary > 10000 or e.job_id like '%MAN%';
not 不是 不为
员工ID不为空的员工
SELECT * FROM EMPLOYees e where e.department_id is not null;
员工ID不是90、60的员工
SELECT * FROM EMPLOYees e where e.department_id not in (90，60);
escape 转义
select * from t_char where a like '%#%%' escape '#';
escape后的’#'可以指定任意字符
select * from t_char where a like '%z%%' escape 'z';
order by 默认升序asc 降序desc
部门ID不在90的员工并按照日期升序
SELECT * FROM EMPLOYees e where e.department_id not in (90) order by e.hire_date;
部门ID不在90的员工并按照日期降序
SELECT * FROM EMPLOYees e where e.department_id not in (90) order by e.hire_date desc;
