--创建表
create table emp01
as
select * from employees
where department_id in (70,80)--
--创建表
create table emp02
as
select * from employees
where department_id in (80,90)
--查询 --并集
select * from employees
where department_id in (70,80)
union all
se…
--子查询 查询last_name为chen的manager信息select employee_id,last_name
from employees
where employee_id(
select manager_id
from employees
where last_nameChen
)
运行结果 --查询
select employee_id,manager_id,department_id
from employees
where manager_id in(
…