[英]Union all in Vertica SQL based on tables with different number of columns?
Hellow i have two tables in Vertica SQL:你好,我在 Vertica SQL 中有两个表:
table 1表格1
col1 col2 col3
1 3 5
2 4 6
table 2表 2
col1 col2
11 33
22 44
And I would like to UNION these two tables, so as as result I would like to have:我想 UNION 这两个表,因此我想拥有:
col1 col2 col3
1 3 5
2 4 6
11 33 NULL
22 44 NULL
How can I do it in vertica我怎样才能在vertica中做到这一点
use null
as follows:使用
null
如下:
select col1, col2, col3 from table1
union
select col1, col2, null from table2
In general, you should use UNION ALL
and define the extra column with whatever default value you want:通常,您应该使用
UNION ALL
并使用您想要的任何默认值定义额外的列:
select col1, col2, col3
from table1
union all
select col1, col2, NULL as col3
from table2;
UNION
incurs overhead for removing duplicates. UNION
会产生删除重复项的开销。 In general, you should use UNION ALL
unless you intend to remove duplicates.通常,除非您打算删除重复项,否则您应该使用
UNION ALL
。
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