相关疑难解决方法(0)

我在pg生产模式下收到此错误,但它在sqlite3开发模式下工作正常.

 ActiveRecord::StatementInvalid in ManagementController#index

PG::Error: ERROR:  column "estates.id" must appear in the GROUP BY clause or be used in an aggregate function
LINE 1: SELECT "estates".* FROM "estates"  WHERE "estates"."Mgmt" = ...
               ^
: SELECT "estates".* FROM "estates"  WHERE "estates"."Mgmt" = 'Mazzey' GROUP BY user_id

@myestate = Estate.where(:Mgmt => current_user.Company).group(:user_id).all

我在匹配表中有以下数据:

5;{"Id":1,"Teams":[{"Name":"TeamA","Players":[{"Name":"AAA"},{"Name":"BBB"}]},{"Name":"TeamB","Players":[{"Name":"CCC"},{"Name":"DDD"}]}],"TeamRank":[1,2]}
6;{"Id":2,"Teams":[{"Name":"TeamA","Players":[{"Name":"CCC"},{"Name":"BBB"}]},{"Name":"TeamB","Players":[{"Name":"AAA"},{"Name":"DDD"}]}],"TeamRank":[1,2]}

我想按名称选择表格中每个最后一个不同的团队.即我想要一个将返回的查询:

6;{"Name":"TeamA","Players":[{"Name":"CCC"},{"Name":"BBB"}
6;{"Name":"TeamB","Players":[{"Name":"AAA"},{"Name":"DDD"}

所以每个团队从上次那个团队出现在表中.
我一直在使用以下(从这里):

WITH t AS (SELECT id, json_array_elements(match->'Teams') AS team FROM matches)
SELECT MAX(id) AS max_id, team FROM t GROUP BY team->'Name';

但这回归:

ERROR: could not identify an equality operator for type json
SQL state: 42883
Character: 1680

Run Code Online (Sandbox Code Playgroud)

我知道Postgres 没有JSON的相等性.我只需要团队名称(字符串)的相等性,该团队中的队员不需要进行比较.

任何人都可以建议另一种方法吗？
以供参考:

SELECT id, json_array_elements(match->'Teams') AS team FROM matches

收益:

5;"{"Name":"TeamA","Players":[{"Name":"AAA"},{"Name":"BBB"}]}"
5;"{"Name":"TeamB","Players":[{"Name":"CCC"},{"Name":"DDD"}]}"
6;"{"Name":"TeamA","Players":[{"Name":"CCC"},{"Name":"BBB"}]}"
6;"{"Name":"TeamB","Players":[{"Name":"AAA"},{"Name":"DDD"}]}"

编辑:我转向text并关注这个问题,我用DISTINCT ON而不是GROUP BY.这是我的完整查询:

WITH t AS (SELECT id, …

我正在尝试在 Hasura 中创建一个函数来查询用户附近的帖子。我得到了那个工作，但我也想订购这些帖子。我收到一个 Postgres 错误，内容为：

“postgres-error : 列“b.Volume”必须出现在 GROUP BY 子句中或用于聚合函数中”

我是 Hasura 和 Postgres 的新手，我不确定您是否被允许做这样的事情。这是我的代码：

CREATE OR REPLACE FUNCTION public.search_posts_near_user(id uuid, distance_kms integer, volume integer)
 RETURNS SETOF user_posts
 LANGUAGE sql
 STABLE
AS $function$
  SELECT  A.id, A.location,
  (SELECT json_agg(row_to_json(B)) FROM "Posts" B
   WHERE (
     ST_Distance(
       ST_Transform(B.location::Geometry, 3857),
       ST_Transform(A.location::Geometry, 3857)
     ) /1000) < distance_kms AND B."Volume" < volume
    ORDER BY B."Volume" Desc
   ) AS nearby_Posts
  FROM users A where A.id = id
$function$