Question

我有一个活动的记录查询在控制台中运行正常但在我在rake任务中使用它时不起作用

这是我的佣金任务的开始：

namespace :attendees do
  desc "Migrate sms plans to receive_sms attribute for attendees"
  task migrate_sms_plans: :environment do
    attendees_with_sms_plans = Attendee.select('attendees.id, attendees.phone, attendees.local_phone').joins(:plans).where('plans.name = ?', "Yes! SMS!")

为什么select语句在我的rails控制台中有效，但在rake任务中使用它时会给我以下错误，如何修复它：

ActiveRecord::StatementInvalid: PG::UndefinedFunction: ERROR:  function count(integer, character varying, character varying) does not exist
LINE 1: SELECT COUNT(attendees.id, attendees.phone, attendees.local_...
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

原来错误不是select语句，而是在下一行：

puts <<-TEXT
    Going to migrate #{attendees_with_sms_plans.count} attendees from "Yes! SMS!" plan to receive_sms: true attribute on Attendee Model
TEXT

我修改为：

puts <<-TEXT
    Going to migrate #{attendees_with_sms_plans.to_a.count} attendees from "Yes! SMS!" plan to receive_sms: true attribute on Attendee Model
TEXT

Answer 1

好吧，猜错了： -

attendees_with_sms_plans = Attendee.select('attendees.id, attendees.phone, attendees.local_phone').joins(:plans).where('plans.name = ?', "Yes! SMS!")

attendees_with_sms_plans将结果为Attendee::ActiveRecord_Relation

并且在调用attendees_with_sms_plans.count时会将结果导入

错误：函数计数（整数，字符变化，字符变化）不存在

表示Postgres does not support count()with more than one column

所以解决方法是，如果size()如此，您可以使用count()： -

attendees_with_sms_plans.size

Answer 2

请使用以下查询检查功能计数是否存在

SELECT n.nspname
FROM pg_extension e
   JOIN pg_namespace n
      ON e.extnamespace = n.oid
WHERE e.extname = 'count';

如果不在search_path上，则您的查询将无法找到该功能。

要在不同的架构中使用扩展，请在以下示例中公开，删除并重新创建它：

DROP EXTENSION count;
CREATE EXTENSION count SCHEMA public;

如何获得在Rails控制台中工作的Active Record查询？

2 个答案: