当 Heroku 在我的本地 Rails 环境中运行良好时，为什么我会在 Heroku 上收到 PG 错误？

Question

我收到以下错误：

ReportsController#return_search (ActiveRecord::StatementInvalid) "PGError: ERROR: syntax error at or near \"FROM\"\nLINE 5: ...OUNT(contact_postalcards.id) AS postalcard_count, FROM \"cont...\n 

它在本地工作正常，但是当我推送到 Heroku 时，我收到错误：

我需要更改什么才能在 Heroku 上的 Postgres 上工作？

@list = Contact.find :all,
  :select => "companies.name AS co_name, 
             companies.id AS comp_id, 
              COUNT(contact_emails.id) AS email_count, 
              COUNT(contact_calls.id) AS call_count, 
              COUNT(contact_letters.id) AS letter_count, 
              COUNT(contact_postalcards.id) AS postalcard_count",

  :conditions => ['contact_emails.date_sent < ? and contact_emails.date_sent > ?', 
                  report_end_date, report_start_date],

  :joins => [
    "LEFT JOIN companies ON companies.id = contacts.company_id",
    "LEFT JOIN contact_emails ON contact_emails.contact_id = contacts.id",
    "LEFT JOIN contact_letters ON contact_letters.contact_id = contacts.id",
    "LEFT JOIN contact_postalcards ON contact_postalcards.contact_id = contacts.id",
    "LEFT JOIN contact_calls ON contact_calls.contact_id = contacts.id"
  ],
  #:group => "companies.id"
   :group => "companies.name"
puts @list[0].attributes.inspect

Answer 1

从错误消息来看：

AS postalcard_count，来自

在您的查询中删除这个逗号，这是您的错误。

Answer 2

看起来这是 PG 特有的，所以我完全改变了数据库结构。