postgresql - 如何替换？列？从子查询输出

Question

如何将名称放在子查询的输出上，而不是?column??

的SELECT输出是：

._______.__________.__________.
|__id___|_?column?_|_?column?_|
|_31886_|____12____|____13____|

我想要的是：

._______.__________.__________.
|__id___|___ages___|_validate_|
|_31886_|____12____|____13____|

我的SELECT样子：

SELECT g.id,
(select dt from pcdhidro where nomepcd=31886 order by datahora asc limit 1),
(select dt from pcdhidro_2003_96 where nomepcd=31886)
FROM gestpcd_2 g
WHERE g.tipo = 'HIDRO' and g.id = 31886

Answer 1

(Select X from Y) AS alias

所以在你的情况下：

SELECT g.id,
(select dt from pcdhidro where nomepcd=31886 order by datahora asc limit 1) as ages,
(select dt from pcdhidro_2003_96 where nomepcd=31886) as validate
FROM gestpcd_2 g
WHERE g.tipo = 'HIDRO' and g.id = 31886