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首先,如果您不使用9.1+,请参阅此问题.

如何安装PostgreSQL 9.1的扩展？

我正在写一个查询,以获得所有球队的所有球员.我没有在应用程序中循环,而是决定使用单个查询来获取所有团队的玩家array_agg().我写的查询如下:

SELECT team_id, array_agg(team_name) AS teamname,
       array_agg(player_id||'##'||player_name) AS playerdetails
FROM team
INNER JOIN players ON team_id = player_team
GROUP BY team_id

这个查询给我的结果如下,在结果集中teamname重复(确切地说是玩家的数量)

team_id             team_name                                                                   playerdetails
1       {Australia,Australia,Australia,Australia}                       {"5##Glenn Donald McGrath","6##Shane Warne","2##Steve Waugh","1##Adam Gilchrist"}
2       {India,India,India,India}                                       {"8##Kapil Dev","11##Saurav Ganguly","3##Rahul Dravid","9##Sachin Tendulkar"}
3       {"South Africa","South Africa","South Africa","South Africa"}   {"12##Gary Kristen","4##Shaun Pollock","7##Jacques Kallis","10##Alan Donald"}

有没有办法像这样返回结果

team_id             team_name                                                                   playerdetails
1                   Australia                       {"5##Glenn Donald McGrath","6##Shane Warne","2##Steve Waugh","1##Adam Gilchrist"}

我使用子查询实现了它,但想知道是否可以在没有子查询的情况下编写它

SELECT team_id, teamname[1], playerdetails
FROM (
  SELECT team_id, array_agg(team_name) AS teamname,
         array_agg(player_id||'##'||player_name) …

假设我在 Postgres 上有一个表，其中 jsonb 列包含{"a": 1, "b": 2}. 现在我想插入一个具有相同 id 和{"b": 10, "c": 20}jsonb 列值的记录。

因此，我希望行的 jsonb 字段包含{"a": 1, "b": 10, "c": 20}. 如何做到这一点？