如何在Postgres中使用数组作为变量？

Question

我有这个.sql脚本：

DO $$
  DECLARE 
    user_list integer[] = (select user_id from user where state = 'ACTIVE');
BEGIN
    CREATE CREATE MATERIALIZED VIEW accounts_with_active_users AS
    select * from accounts where user_account IN (user_list);
    ...

    CREATE CREATE MATERIALIZED VIEW accounts_without_active_users AS
    select * from accounts where user_account NOT IN (user_list);
    ...
END $$;

但是我总是有这个错误：

ERROR: cannot cast type integer to integer[]

我也尝试过用这个词array之前有相同的结果：

user_list integer[] = array(...)

Answer 1

您正在尝试将行集分配给数组。你可以用array_agg()它代替。

user_list integer[] = (select array_agg(user_id) from users where state = 'ACTIVE');

话虽如此，恕我直言，这并不能真正帮助您创建物化视图。只需内联您的选择

CREATE CREATE MATERIALIZED VIEW accounts_with_active_users AS
    SELECT * FROM accounts WHERE user_account IN (
        SELECT user_id FROM users WHERE state = 'ACTIVE'
    );

或创建一个active_users视图

CREATE VIEW active_users AS SELECT * FROM users WHERE state = 'ACTIVE';

并用它代替

CREATE CREATE MATERIALIZED VIEW accounts_with_active_users AS
    SELECT * FROM accounts WHERE user_account IN (
        SELECT user_id FROM active_users;
    );