Sql以特定方式连接两个表格

Question

两个表格具有相同的结构，只有不同的值;

T1

 
id param1 param2 
--- ------ ------ 
id1 1  100 
id1 2  101 

T2

 
id param1 param2 
--- ------ ------ 
id1 1  501 
id1 2  502 
id1 3  503 

我需要的是SQL查询，这将导致这样的表：

 
id  param1 param2 param1 param2
 
id1 1  100 
id1 2  101 
id1     1  501 
id1     2  502 
id1     3  503 

试着用不同的连接，但没有运气。可能吗？

Answer 1

select id1, param1, param2, null, null from t1 
union all 
select id1, null, null, param1, param2 from t2 

如果你需要T1 T2之前记录总是来，然后

select id1, param1, param2, param1_b, param2_b 
from 
(
select 1 as sorter, id1, param1, param2, null as param1_b, null as param2_b from t1 
union all 
select 2 as sorter, id1, null, null, param1, param2 from t2 
) X 
order by sorter