select ename,sal from emp where sal <>5000;select ename,sal from emp where sal !=5000;
2.3查询薪水为1600到3000的员工
#between … and …select empno, ename, sal from emp where sal between1600and3000;#>=和<=select empno, ename, sal from emp where sal >=1600and sal <=3000;
2.4查询哪些人津贴为NULL
select ename,sal,comm from emp where comm isnull;
2.5查询哪些人津贴不为NULL
select ename,sal,comm from emp where comm isnotnull;
2.6查询哪些人没有津贴
select ename,sal,comm from emp where comm isnullor comm =0;
2.7查询工作岗位为MANAGER ,薪水大于2500的员工
select*from emp where job='MANAGER'and sal >2500;
2.8查询出job为manager 或者 job为salesman的员工
#or操作符select*from emp where job='MANAGER'or job='SALESMAN';#in操作符select*from emp where job in('manager','salesman');
2.9查询出薪水包含1600和薪水包含3000的员工
select*from emp where sal in(1600,3000);
2.10查询出薪水不包含1600和薪水不包含3000的员工
#<>、and操作符select*from emp where sal <>1600and sal <>3000;#not、or操作符select*from emp wherenot(sal =1600or sal =3000);#not、in操作符select*from emp where sal notin(1600,3000);
2.11查询出津贴不为null的所有员工
select*from emp where comm isnotnull;
2.12条件查询-like
#查询姓名以M开头所有的员工select ename from emp where ename like'M%';#查询姓名以N结尾的所有员工select ename from emp where ename like'%M';#查询姓名中包含O的所有员工select ename from emp where ename like'%O%';#查询姓名中第二个字符为A的所有员工select ename from emp where ename like'_A%'
3.排序
3.1单一字段排序
#按照薪水从小到大排序select*from emp orderby sal;#取得工作岗位为MANAGER的员工,按照薪水由小到大排序select*from emp where job='MANAGER'orderby sal;
3.2手动指定排序顺序
#手动指定按照薪水由小到大排序select*from emp orderby sal asc;#手动指定按照薪水由大到小排序select*from emp orderby sal desc;
3.3多个字段排序
#按照工作岗位和薪水倒序select*from emp orderby job desc, sal desc;
3.4按别名排序
#查询每个员工一年的薪水,并显示字段名字为nianxin,按nianxin降序排序select ename,sal,sal*12 nianxin from emp orderby nainxin desc;