ruby-on-rails - PG::rails 中 group_date gem 出错

Question

我一直在使用它来获取一天的每小时数据，所以我尝试过这样

@getting_each_day = Order.group_by_hour_of_day("2014-08-22 00:00:00").count

但它显示 postgresql 错误.....

PG::Error: ERROR: syntax error at or near "00"
LINE 1: ...UNT() AS count_all, EXTRACT(HOUR from 2014-08-22 00:00:00::...
^
: SELECT COUNT() AS count_all, EXTRACT(HOUR from 2014-08-22 00:00:00::timestamptz AT TIM
ZONE 'Asia/Muscat' - INTERVAL '0 hour')::integer AS hour_of_day FROM "orders" WHERE (2014- 
08-22 00:00:00 IS NOT NULL) GROUP BY EXTRACT(HOUR from 2014-08-22 00:00:00::timestamptz AT
TIME ZONE 'Asia/Muscat' - INTERVAL '0 hour')::integer

但它正在使用Order.group_by_hour_of_day(:created_at).count

我的查询有什么问题吗？另外，我尝试过使用时区，但得到了同样的错误。

Answer 1

您可以简单地使用 group （不使用 gem）在 where 子句中指定您的目标日期：

Order.where('date(created_at) = ?', "2014-08-22").select('EXTRACT(HOUR from created_at)').group('EXTRACT(HOUR FROM created_at)').count