查找财务部年龄低于开发部员工年龄的员工的姓名。select name from employees where birthday in (select birthday from employees where departmentid in (select departmentid from departments where departmentname = '财务部'))
and ((select birthday from employees where departmentid in (select departmentid from departments where departmentname = '财务部'))
>all (select birthday from employees where departmentid in (select departmentid from departments where departmentname = '开发部')))
and ((select birthday from employees where departmentid in (select departmentid from departments where departmentname = '财务部'))
>all (select birthday from employees where departmentid in (select departmentid from departments where departmentname = '开发部')))
查找财务部年龄低于开发部员工平均年龄的员工的姓名。
查找财务部年龄低于开发部员工最高年龄的员工的姓名。
查找财务部年龄低于开发部员工最低年龄的员工的姓名。
select name from employees where birthday in (select birthday from employees where departmentid in (select departmentid from departments where departmentname = '财务部'))
and birthday >all (select birthday from employees where departmentid in (select departmentid from departments where departmentname = '开发部'))
改好了,这样好像可以了