# 工资最高的人 现有员工信息表如下: ```postgresql create table employee ( id serial primary key, name text, dept text, salary money ); ``` 下面哪条查询,可以给出每个部门工资最高的员工的 id, name, dept, salary 四项信息? ## 答案 ```postgresql select l.id, l.name, l.dept, l.salary from employee as l join (select max(salary) as salary, dept from employee group by dept) as r on l.dept = r.dept and l.salary = r.salary ``` ## 选项 ### select 与 group by 不匹配 ```postgresql select id, name, dept, max(salary) from employee group by dept; ``` ### group by 不对 ```postgresql select id, name, dept, max(salary) from employee group by dept, id, name; ``` ### group by 不对 ```postgresql select id, name, dept, max(salary) from employee group by dept, id, name having salary = max(salary); ``` ### 结构错误 ```postgresql select id, name, dept, max(salary) from employee where salary=max(salary) group by dept; ```