C# Postgres json_agg包含列标题-json不正确？

接下来，我有一个SQL查询，返回下表：

team (json)
"{"Name":"TeamA","Players":[{"Name":"CCC"},{"Name":"BBB"}]}"
"{"Name":"TeamB","Players":[{"Name":"AAA"},{"Name":"DDD"}]}"

我需要将其聚合为JSON，以便在我的应用程序中使用。我正在使用以下命令：

SELECT json_agg(u) FROM (SELECT DISTINCT ON (t.team->>'Name') t.team
FROM   matches m, json_array_elements(m.match->'Teams') t(team)
ORDER  BY t.team->>'Name', m.id DESC) AS u

返回：

"[{"team":{"Name":"TeamA","Players":[{"Name":"CCC"},{"Name":"BBB"}]}}, 
 {"team":{"Name":"TeamB","Players":[{"Name":"AAA"},{"Name":"DDD"}]}}]"

因此，它似乎在每个对象之前都放置了一个“team”标记。这无法在我的C#应用程序中正确序列化。在阅读之后，我相信这可能是不正确的。这是正确的吗

我想以以下形式得到它：

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

我相信这是正确的JSON，它将在我的应用程序中正确解析

我在C#中使用的类如下所示：

//[JsonObject(Title="team")]  I tried adding this too
public class Team
{
    public string Name { get; set; }
    public List<Player> Players { get; set; }
}

和样本数据：

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]}

---

请参阅了解更多信息。

从某种意义上说，它是正确的JSON，它是有效的，但它显然不是您想要的。因此，答案取决于“正确”的定义。我们将假定您想要的是“正确的”

您要求它聚合

u

，这是一个列为

team

的结果集。这意味着它必须将此信息添加到结果中。您应该只要求聚合

u.team

，这是您想要的字段。然后你会得到你想要的结果

WITH matches as
(
select 5 as id, '{"Id":1,"Teams":[{"Name":"TeamA","Players":[{"Name":"AAA"},{"Name":"BBB"}]},{"Name":"TeamB","Players":[{"Name":"CCC"},{"Name":"DDD"}]}],"TeamRank":[1,2]}'::json as match
union all
select 6 as id, '{"Id":2,"Teams":[{"Name":"TeamA","Players":[{"Name":"CCC"},{"Name":"BBB"}]},{"Name":"TeamB","Players":[{"Name":"AAA"},{"Name":"DDD"}]}],"TeamRank":[1,2]}' as match
)
SELECT json_agg(u.team) FROM (
SELECT DISTINCT ON (t.team->>'Name') t.team
FROM   matches m, json_array_elements(m.match->'Teams') t(team)
ORDER  BY t.team->>'Name', m.id DESC) AS u;

结果:

[{“姓名”：“车队”、“球员”：[{“姓名”：“CCC”}，{“姓名”：“BBB”}，
{“Name”：“TeamB”，“Players”：[{“Name”：“AAA”}，{“Name”：“DDD”}]}]

---

使用此链接并检查json是否有效。我检查了你的json，它似乎无效！！两者似乎都是有效的。不过，有额外的团队标记似乎是多余的？它对我来说似乎有效，它只是有一个不必要的1元素数组，其中包含一个1键对象。由于您没有提供示例数据和表定义，因此我无法真正帮助您；也许你应该修正这个问题，完成后在这里发表评论。@CraigRinger更新了表定义和样本数据。哇，真是太容易了。谢谢。

WITH matches as
(
select 5 as id, '{"Id":1,"Teams":[{"Name":"TeamA","Players":[{"Name":"AAA"},{"Name":"BBB"}]},{"Name":"TeamB","Players":[{"Name":"CCC"},{"Name":"DDD"}]}],"TeamRank":[1,2]}'::json as match
union all
select 6 as id, '{"Id":2,"Teams":[{"Name":"TeamA","Players":[{"Name":"CCC"},{"Name":"BBB"}]},{"Name":"TeamB","Players":[{"Name":"AAA"},{"Name":"DDD"}]}],"TeamRank":[1,2]}' as match
)
SELECT json_agg(u.team) FROM (
SELECT DISTINCT ON (t.team->>'Name') t.team
FROM   matches m, json_array_elements(m.match->'Teams') t(team)
ORDER  BY t.team->>'Name', m.id DESC) AS u;