具有不同列数的联盟

Question

我在第一个表中有三列,第二个表有一列存在于第一个表中,2列我想要添加.

例如:

select  c1 as col1, c2 as col2, c3 as col3
from    Table1
union
select  c1, c4 as col4, c5 as col5
from    Table2

expected Result:

col1,col2,col3,col4,col5

Answer 1

只需添加null或任何其他默认值作为静态列

select  c1 as col1, 
        c2 as col2, 
        c3 as col3, 
        null as col4, 
        null as col5
from    Table1
union
select  c1, 
        null, 
        null, 
        c4,
        c5
from    Table2