Question

我正在为我的客户端从遗留数据库中删除重复项，我发现了一个MySQL查询来做到这一点。我想创建一个Rake任务来运行生产服务器的查询。我该怎么做？

MySQL查询：

    select * from community_event_users;
    create table dups as
      select distinct username, count(*)
      from community_event_users group by username
      having count(*) > 1;
    delete community_event_users from community_event_users inner join dups
    on community_event_users.username = dups.username;

    insert into community_event_users select username from dups;

Answer 1

如果您使用的是Rails并使用ActiveRecord，则只需使用：

ActiveRecord::Base.execute(my_sql)

ActiveRecord::Base.connection.execute(my_sql)

my_sql是你的SQL字符串。

Answer 2

对于 Rails 5 及更高版本，您最好使用：

ApplicationRecord.connection.execute <<~END_OF_SQL
  YOUR QUERY HERE
END_OF_SQL

如何从rake任务运行MySQL查询？

2 个答案: