【Oracle学习笔记-5--】集合操作之union，intersect和minus操作-CFANZ编程社区

--union并操作

select e.employee_id,e.last_name from hr.employees e

where e.last_name like 'C%'

union

select e.employee_id,e.last_name from hr.employees e

where e.last_name like 'S%';

--等价于

select e.employee_id,e.last_name from hr.employees e

where e.last_name like 'C%'or e.last_name like 'S%';

【Oracle学习笔记-5--】集合操作之union，intersect和minus操作_intersect

-- intersect交集操作

select e.employee_id,e.last_name from hr.employees e

where e.last_name like 'C%'or e.last_name like 'S%'

intersect

select e.employee_id,e.last_name from hr.employees e

where e.last_name like 'S%'or e.last_name like 'T%';

--等价于

select e.employee_id,e.last_name from hr.employees e

where e.last_name like 'S%';

【Oracle学习笔记-5--】集合操作之union，intersect和minus操作_intersect_02

--minus差操作

select e.employee_id,e.last_name from hr.employees e

where e.last_name like 'C%'or e.last_name like 'S%'

minus

select e.employee_id,e.last_name from hr.employees e

where e.last_name like 'S%'or e.last_name like 'T%';

--等价于

select e.employee_id,e.last_name from hr.employees e

where e.last_name like 'C%';

【Oracle学习笔记-5--】集合操作之union，intersect和minus操作_javascript_03