Mysql语句

1. select empno,ename,sal from emp;

2. select * from emp;

排序检索:

1. select * from emp order by sal;

2. select * from emp order by sal desc, hiredate;  工资降序,入社日期升序

3. select * from emp orber by 2,3; 按照第2,3行排序

过滤数据:

1. select * from emp where sal>500;

2.  select * from emp where sal<>500;= select * from emp where sal!=500;

3.  select * from emp where sal between 500 and 5000;

4.  select * from emp where hiredate=‘2015-11-12‘ or hiredate=‘2003-10-09‘ and sal=1500;

应改成  select * from emp where (hiredate=‘2015-11-12‘ or hiredate=‘2003-10-09‘) and sal=1500;

否则and有优先权.

5.  select * from emp where sal in (500,1500); =  select * from emp where sal=500 or sal=1500;

6.  select * from emp where not sal=2000;

通配符:

1.  select * from emp where empno like ‘10%‘;

2. select * from emp where sal like ‘50%‘;

3.  select * from emp where job like ‘%师%‘; %表示0个以上,包含0

4. select * from emp where job like ‘__师%‘;  两个_ 表示前面要有2个字, 有几个就要补充几个.

5.  select * from emp where ename like ‘l%‘;  l开头的

6.  select CONCAT(ename,‘   (‘,job,‘)‘) as title from emp; 组成一个新的列

7.  select ename,sal*12 as salary from emp where sal>500; ename, salary(别名)两个列

使用数据处理函数:

1. 

Mysql语句

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