如何使SQL返回相同的數據

Question

select id, bossid 
from employees 
where id in (22299, 22299) 

這導致

id |bossid 
22299|20529 

我想

id |bossid 
22299|20529 
22299|20529 

有沒有一種方法，使數據庫返回的結果也是這樣嗎？

Answer 1

使用union作爲

select id, bossid 
from employees 
where id = 22299 
UNION 
select id, bossid 
from employees 
where id = 22299 

Answer 2

一種方法是使用union all：

select id, bossid 
from employees 
where id in (22299) 
union all 
select id, bossid 
from employees 
where id in (22299); 

另一個用途join這可能看起來像：

select e.id, e.bossid 
from employees e join 
    (select 22299 as id union all select 22299 
    ) ids 
    on e.id = ids.id; 

或者，只是使用cross join：

select e.id, e.bossid 
from employees e join 
    (select 1 as n union all select 2 
    ) ids;