两列 UNION 的结果

Question

我正在从两个表中查询姓名：

with data_1 as (
select names from tbl1),

data_2 as (
select names from tbl2)

select * from data_1
union
select * from data_2

我在一个列中得到了我想要的结果。

现在我想知道是否可以在两个不同的列中获得结果，例如："names_from_data1", "names_from_data2"

或另一种识别每个名称来源的方法：data_1 或 data_2

Answer 1

您可以添加硬编码列来指示来源：

with data_1 as (
select names, 'tbl1' as source from tbl1),

data_2 as (
select names, 'tbl2' as source from tbl2)

select * from data_1
union
select * from data_2

两列 UNION 的结果

Results of an UNION in two columns

sql

presto