如何将多行合并到同一个id mysql

Question

我是新来这里张贴，但社区一直是我最好的资源，我的项目到目前为止。我是一个哑巴/傀儡Mysql“想要成为”，我正处于一个让我发疯的项目中。

我有一个来自wordpress插件buddypress的表，它将meta_key和meta_values配对，以创建类似于分类法的东西。我的职责是使用这些配对值来实现高级组搜索。这是原来的桌子：

--------------------------------------------
id | group_id | meta_key           | meta_value
--------------------------------------------
1  | 1        | time-zone          | Kwajalein
2  | 1        | playstyle          | hardcore
3  | 1        | recruiting-status  | Open
4  | 1        | ilvl               | 115
5  | 1        | main-raid          | Final Coil of Bahamut
6  | 1        | voicechat          | fc.teamspeak3.com

等等..。

使用视图，我设法为乞丐创建了一个更友好的搜索表：

gid| time-zone| playstyle  | main-raid
--------------------------------------------
1  |          |            | 
1  |Kwajalein |            | 
1  |          | hardcore   | 
1  |          |            | 
1  |          |            | Final Coil of Bahamut
1  |          |            | 

以下是视图代码：

SELECT distinct
group_id AS 'gid',
IF(meta_key='recruiting-status',meta_value,'') AS 'Recruitment',
IF(meta_key='server',meta_value,'') AS 'server',
IF(meta_key='time-zone',meta_value,'') AS 'tzone',
IF(meta_key='main-raid',meta_value,'') AS 'raid',
IF(meta_key='raid-days',meta_value,'') AS 'days',
IF(meta_key='playstyle',meta_value,'') AS 'playstyle',
IF(meta_key='raid-progression',meta_value,'') AS 'progression',
IF(meta_key='raid-time',meta_value,'') AS 'time',
IF(meta_key='tanker-spot',meta_value,'') AS 'tank',
IF(meta_key='healer-spot',meta_value,'') AS 'healer',
IF(meta_key='melee-dps-spot',meta_value,'') AS 'melee',
IF(meta_key='ranged-dps-spot',meta_value,'') AS 'ranged',
IF(meta_key='magic-dps-spot',meta_value,'') AS 'magic',
IF(meta_key='ilvl',meta_value,'') AS 'ilvl',
IF(meta_key='voicechat',meta_value,'') AS 'voice',
IF(meta_key='voicechatpass',meta_value,'') AS 'voicep',
FROM wpstatic_bp_groups_groupmeta

重点是，我需要合并结果(视图)，以便所有的group_id=1或2或3等都站在一排，如下所示：

gid| time-zone| playstyle  | main-raid
--------------------------------------------
1  |Kwajalein | hardcore   | Final Coil of Bahamut
2  |SaoPaulo  | regular    | Second Coil of Bahamut

等

有人能帮我吗？

Answer 1

只需将IF包围在一个MAX中，或者将捕获非空字符串(例如GROUP_CONCAT)的另一个聚合函数中，然后添加一个GROUP BY group_id添加结束。例如,

SELECT
group_id AS gid,
MAX(IF(meta_key='recruiting-status',meta_value,'')) AS 'Recruitment',
MAX(IF(meta_key='server',meta_value,'')) AS 'server',
...
FROM wpstatic_bp_groups_groupmeta
GROUP BY group_id