avg.md

# 平均值练习

Joe 想要得到 employee 表

```mysql
create table employee
(
    id     serial primary key,
    name   varchar(256),
    dept   varchar(256),
    salary decimal(12, 4)
);
```

中每个部门的平均工资信息，这条查询应该怎么写？

## 答案

```mysql
select dept, avg(salary) from employee group by dept;
```

## 选项

### A

```mysql
select dept, avg(salary) from employee;
```

### B

```mysql
select dept, avg(salary) from employee;
```

### C

```mysql
select dept, avg(salary) from employee;
```

### D

```mysql
select dept, avg(salary) from employee ;
```