PostgreSQL - 组合来自多个查询的结果行

Question

我无法在同一个table.column中添加两个列，但有两个不同的值。

如何将以下两个查询一起添加到两个新列中，每个列都有自己的值;

SELECT
    ... more columns ...
    components.description,
FROM
    ...
WHERE
    graphiccards.id = systems.id AND
    components.id = graphiccards.component_id;

SELECT
    components.description
FROM
    ...
WHERE
    components.id = mainboards.component_id AND
    mainboards.id = systems.mainboard_id

我希望这两个结果位于两个不同列的同一行。

https://gyazo.com/de8100b645d6e0ccad3d1ec664907246

Answer 1

您可能希望查看UNION运算符

select
  components.description
  stuff as second_column
from mytable where conditions

union

select
  components.description
  stuff2 as second_column
from mytable2 where conditions2

您只需要确保具有相同名称的相同nr列。