all.md

# ALL

Joe 想从员工表

```sql
create table employee(
    id int primary key auto_increment,
    dept_id int,
    name varchar(256),
    post varchar(16)
)
```

中找出所有其所在部门没有助理（post 为 `assistant`）的员工信息。由于 Joe 没有其它表的查询权限，他只能查询员工表，这个查询应该是：

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* `show tables;` 列出所有表

## 答案

```sql
select id, name, dept 
from employee as o
where 'assistant' != 
      all(select post 
          from employee as i 
          where o.dept = i.dept); 
```

## 选项

### A

```sql
select id, name, dept 
from employee as o
where 'assistant' = 
      all(select post 
          from employee as i 
          where o.dept = i.dept); 
```

### B

```sql
select id, name, dept 
from employee as o
where 'assistant' != 
      all(select post 
          from employee as i 
          where o.dept = i.dept); 
```

### C
```sql
select id, name, dept 
from employee as o
where 'assistant' != 
      all(select post 
          from employee as i); 
```

### D

```sql
select id, name, dept 
from employee as o
where 'assistant' != 
      ANY(select post 
          from employee as i 
          where o.dept = i.dept); 
```