一次查询多个数据库

Querying multiple databases at once(一次查询多个数据库)

问题描述

我有 WordPress 实例，每个实例都在自己的数据库中.对于更新，我需要查询所有活动插件，这些插件存储在表wp_options"中并可通过

I have WordPress instances with each in its own database. For an update I need to query all active plugins, that are stored in a table 'wp_options' and accessible via

WHERE option_name='active_plugins'

如何访问所有活动插件设置(分布在多个数据库中)并将它们输出到一个 SQL 结果中?我知道 database.tablename 语法，但如何使用上述 Where 语句从那里继续?

How can I access all active plugin settings (spread over multiple databases) and output them in one single SQL result? I know the database.tablename syntax, but how do I go on from there with the above Where statement?

单个数据库中的请求如下所示:

A request in a single database would look like this:

SELECT option_value
  FROM `database`.`wp_options`
 WHERE option_name="active_plugins"

推荐答案

SELECT option_value
 FROM `database1`.`wp_options`
  WHERE option_name="active_plugins"
UNION
SELECT option_value
 FROM `database2`.`wp_options`
  WHERE option_name="active_plugins"

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