Sql Rails 4将查询与地理位置找到的预定对象连接起来

Sql Rails 4将查询与地理位置找到的预定对象连接起来,sql,ruby-on-rails,join,ruby-on-rails-4,Sql,Ruby On Rails,Join,Ruby On Rails 4,模型 我想写下面这样的东西,但我知道不是这样的 Trial.joins("LEFT JOIN locations ON locations.trial_id = trials.id AND locations = s_locs") 如果有一种Rails 4方式和一种更类似SQL的方式,我希望看到这两种方式,因为我正在努力更好地学习SQL Trial.joins("LEFT JOIN locations ON locations.trial_id = trials.id") Trial.joi

模型

我想写下面这样的东西,但我知道不是这样的

Trial.joins("LEFT JOIN locations ON locations.trial_id = trials.id AND locations = s_locs")
如果有一种Rails 4方式和一种更类似SQL的方式,我希望看到这两种方式,因为我正在努力更好地学习SQL

Trial.joins("LEFT JOIN locations ON locations.trial_id = trials.id")
Trial.joins("LEFT JOIN locations ON locations.trial_id = trials.id AND locations = s_locs")