在 WHERE ... IN 条件下使用 JSONB_ARRAY_ELEMENTS

Question

在线扑克玩家可以选择购买游戏室 1 或游戏室 2 的使用权。

并且可以暂时禁止作弊。

CREATE TABLE users (
        uid SERIAL PRIMARY KEY,

        paid1_until timestamptz NULL,     -- may play in room 1
        paid2_until timestamptz NULL,     -- may play in room 2

        banned_until timestamptz NULL,    -- punished for cheating etc.
        banned_reason varchar(255) NULL
);

这里上面table填充了4条测试记录：

INSERT INTO users (paid1_until, paid2_until, banned_until, banned_reason)
VALUES (NULL, NULL, NULL, NULL),
       (current_timestamp + interval '1 month', NULL, NULL, NULL),
       (current_timestamp + interval '2 month', current_timestamp + interval '4 month', NULL, NULL),
       (NULL, current_timestamp + interval '8 month', NULL, NULL);

所有 4 条记录都属于同一个人 - 通过不同的社交网络（例如通过 Facebook、Twitter、Apple Game Center 等）对自己进行了身份验证

我正在尝试创建一个存储函数，它将获取数字用户 ID 列表（作为 JSON 数组）和属于同一个人的 merge 记录合并到一条记录中 - 不会丢失她的付款或惩罚：

CREATE OR REPLACE FUNCTION merge_users(
        IN in_users jsonb,
        OUT out_uid integer)
        RETURNS integer AS
$func$
DECLARE
        new_paid1 timestamptz;
        new_paid2 timestamptz;
        new_banned timestamptz;
        new_reason varchar(255);
BEGIN
        SELECT min(uid),
                current_timestamp + sum(paid1_until - current_timestamp),
                current_timestamp + sum(paid2_until - current_timestamp),
                max(banned_until)
        INTO
                out_uid, new_paid1, new_paid2, new_banned
        FROM users 
        WHERE uid IN (SELECT JSONB_ARRAY_ELEMENTS(in_users));

        IF out_uid IS NOT NULL THEN
                SELECT banned_reason
                INTO new_reason
                FROM users
                WHERE new_banned IS NOT NULL
                AND banned_until = new_banned
                LIMIT 1;

                DELETE FROM users
                WHERE uid IN (SELECT JSONB_ARRAY_ELEMENTS(in_users))
                AND uid <> out_uid;

                UPDATE users 
                SET paid1_until = new_paid1,
                    paid2_until = new_paid2,
                    banned_until = new_banned,
                    banned_reason = new_reason
                WHERE uid = out_uid;
        END IF; 
END
$func$ LANGUAGE plpgsql;

不幸的是，它的使用会导致以下错误：

# TABLE users;
 uid |          paid1_until          |          paid2_until          | banned_until | banned_reason 
-----+-------------------------------+-------------------------------+--------------+---------------
   1 |                               |                               |              | 
   2 | 2016-03-27 19:47:55.876272+02 |                               |              | 
   3 | 2016-04-27 19:47:55.876272+02 | 2016-06-27 19:47:55.876272+02 |              | 
   4 |                               | 2016-10-27 19:47:55.876272+02 |              | 
(4 rows)

# select merge_users('[1,2,3,4]'::jsonb);
ERROR:  operator does not exist: integer = jsonb
LINE 6:         WHERE uid IN (SELECT JSONB_ARRAY_ELEMENTS(in_users))
                          ^
HINT:  No operator matches the given name and argument type(s). You might need to add explicit type casts.
QUERY:  SELECT min(uid),
                current_timestamp + sum(paid1_until - current_timestamp),
                current_timestamp + sum(paid2_until - current_timestamp),
                max(banned_until)
                                                                               FROM users 
        WHERE uid IN (SELECT JSONB_ARRAY_ELEMENTS(in_users))
CONTEXT:  PL/pgSQL function merge_users(jsonb) line 8 at SQL statement

请帮我解决问题。

这里是 a gist with SQL code 为了您的方便。

Answer 1

jsonb_array_elements() is a set of jsonb elements, therefore you need add explicit cast of uid to jsonb with to_jsonb() function, IN will be replaced with <@ 运算符的结果：

WITH t(val) AS ( VALUES
  ('[1,2,3,4]'::JSONB)
)
SELECT TRUE
FROM t,jsonb_array_elements(t.val) element
WHERE to_jsonb(1) <@ element;

对于您的情况，代码段应调整为：

...SELECT ...,JSONB_ARRAY_ELEMENTS(in_users) user_ids
WHERE to_jsonb(uid) <@ user_ids...

在 WHERE ... IN 条件下使用 JSONB_ARRAY_ELEMENTS

Using JSONB_ARRAY_ELEMENTS with WHERE ... IN condition

postgresql

select

where-in

postgresql-json

postgresql-9.5