Question

我要做的就是按照过去7天内的展示次数（在有人查看帖子时创建展示）来订购帖子。这是我的命名范围

scope :popular_last_week, unscoped
    .select("websites.*, COUNT(impressions.id) AS counted_impressions")
    .joins("INNER JOIN impressions ON websites.id = impressions.impressionable_id")
    .where("impressions.created_at >= ?", 7.days.ago)
    .where(:is_published => true)
    .group("websites.id")
    .order("counted_impressions DESC")

（“counts_impressions”用于避免帖子记录发生冲突）

然而，这会产生以下无效的SQL（counting_impressions不是有效列）：

SELECT COUNT(*) AS count_all, websites.id AS websites_id FROM "websites" INNER JOIN impressions ON websites.id = impressions.impressionable_id WHERE "websites"."is_published" = 't' AND (impressions.created_at >= '2013-01-11 17:48:03.954542') GROUP BY websites.id ORDER BY counted_impressions

似乎只是忽略了select语句。我在哪里出错，或者我该怎么做才能使SQL语句：

SELECT websites.*, COUNT(impressions.id) AS counted_impressions FROM "websites" INNER JOIN impressions ON websites.id = impressions.impressionable_id WHERE "websites"."is_published" = 't' AND (impressions.created_at >= '2013-01-11 17:42:57.771777') GROUP BY websites.id ORDER BY counted_impressions DESC

Answer 1

试试这个：

  scope :popular_last_week, unscoped
    .select(arel_table[Arel.star])
    .select(Website.arel_table[:id].count.as("counted_impressions"))
    .joins("INNER JOIN impressions ON websites.id = impressions.impressionable_id")
    .where("impressions.created_at >= ?", 7.days.ago)
    .where(:is_published => true)
    .group("websites.id")
    .order("counted_impressions DESC")

Answer 2

似乎查询应该是：

SELECT count(*) AS impression_count, w.id AS website_id 
FROM websites as w
INNER JOIN impressions as i ON w.id = i.impressionable_id 
WHERE w.is_published = 't' AND i.created_at >= '2013-01-11 17:48:03.954542'
GROUP BY w.id 
ORDER BY impression_count DESC;

好像你可以跳过这个查询中的连接，然后对下一个查询运行“is_published”检查以获取实际的帖子数据...假设你只是使用这个查询来获取一个ID的列表第二个获取数据的查询。

在Rails Group By Query中忽略Order By

2 个答案: