【大数据系列之MySQL】（十一）：MySQL中select语句查询用法

select 字段名 from 表名;

select last_name from employees;

select 字段1, 字段2 from 表名;

select last_name, salary from employees;

select 全部字段名 from 表名;
select * from 表名;

select employee_id, first_name, last_name from employees;
select * from employees;

# NAME是MySQL的关键字，下面写法会报错
select NAME from employees;

# 正确写法
select `NAME` from employees;

select 100;

select 'abc';

select 100+50;

select max(salary) from employees;

# 方式一
select 字段名 as 新字段名 from 表名;
select last_name as name from employees;

# 方式二
select 字段名 新字段名 from 表名;
select last_name name from employees;

select last_name as 'last name' from employees;

select distinct department_id from employees;

select concat(字段1, 字段2) from 表名;