Rails Mysql Group by strftime 查询在生产中不起作用

Question

我在 Rails 中有一个查询，该查询正在开发中而不是在生产中。查询是：

Event.where("created_at > ? AND name = ? AND game = ?", 3.month.ago, Event::TYPE_USER_SESSION, PLATFORM_CODE).group("strftime('%Y-%m-%d 00:00:00 UTC', created_at, '-6 days', 'weekday 0')").distinct.count(:user_id)

翻译成：

SELECT DISTINCT COUNT(DISTINCT "events"."user_id") AS count_user_id, strftime('%Y-%m-%d 00:00:00 UTC', created_at, '-6 days', 'weekday 0') AS strftime_y_m_d_00_00_00_utc_created_at_6_days_weekday_0 FROM "events" WHERE (created_at > '2015-05-05 11:51:32.292908' AND name = 'user_session' AND game = 'LK') GROUP BY strftime('%Y-%m-%d 00:00:00 UTC', created_at, '-6 days', 'weekday 0')

在 development works 使用 sqlite3，但在使用 mysql 的生产中，我收到此错误：

ActiveRecord::StatementInvalid: Mysql2::Error: FUNCTION monkiland.strftime does not exist: SELECT DISTINCT COUNT(DISTINCT `events`.`user_id`) AS count_user_id, strftime('%Y-%m-%d 00:00:00 UTC', created_at, '-6 days', 'weekday 0') AS strftime_y_m_d_00_00_00_utc_created_at_6_days_weekday_0 FROM `events` WHERE (created_at > '2015-05-05 11:52:09.879454' AND name = 'user_session' AND game = 'LK') GROUP BY strftime('%Y-%m-%d 00:00:00 UTC', created_at, '-6 days', 'weekday 0')

在我的 gemfile 中

group :production do
  gem 'mysql2', '0.3.17'
end

group :development do
  gem 'sqlite3'
end

提前致谢！！！

Answer 1

使用Data_Format()函数，类似于strftime()。