postgresql 表继承

可以按如下语句创建表

CREATE TABLE capitals (
  name       text,
  population real,
  altitude   int,    -- (in ft)
  state      char(2)
);
CREATE TABLE non_captals (
  name       text,
  population real,
  altitude   int     -- (in ft)
);
CREATE VIEW cities AS
  SELECT name, population, altitude FROM capitals
    UNION
  SELECT name, population, altitude FROM non_capitals;

使用表继承

CREATE TABLE cities (
  name       text,
  population real,
  altitude   int     -- (in ft)
);
CREATE TABLE capitals (
  state      char(2)
) INHERITS (cities);

一张表可以继承多张表

往cities表里插入几条数据

再往capitals插入数据

查询时使用如下语句查询

SELECT name, altitude
  FROM cities
  WHERE altitude > 500;

可以看到把wuhan也查出来了

也可以只查一张表里面的

SELECT name, altitude
    FROM ONLY cities
    WHERE altitude > 500;

 结果没有wuhan