字符串转换为在数量where子句
问题描述：
我有以下where子句：字符串转换为在数量where子句
OnlineCourseRegistration.where(course_class_id: 6, status: "Completed")
=> #<OnlineCourseRegistration id: 142, cart_id: 150, user_id: 7069, course_class_id: 681, created_at: "2017-07-15 22:06:06", updated_at: "2017-07-20 23:59:01", exam_attempts: 1, exam_completed_at: "2017-07-20 23:57:32", evaluation_completed_at: "2017-07-20 23:59:01", status: "Completed", score: "87", add_extension: false, retest_cart_id: nil, retest_purchased_at: nil>
我还想补充一点，比分会是大于70，所以像...
OnlineCourseRegistration.where(course_class_id: 681, status: "Completed", :score.to_i > 70).last
...但当然，这是行不通的。在where子句中有没有办法做到这一点？
答
ActiveRecord的地方接受string作为查询构造
OnlineCourseRegistration.where("course_class_id = ? AND status = ? AND score > ?", 681, "Completed", 70).last
+0
这工作......谢谢！我确实需要调整一下。因为分数是一个字符串，我不得不在分数上加上引号“OnlineCourseRegistration.where”（“course_class_id =？AND status =？AND score>？”，681，“Completed”，“70”）' – Lumbee
答
如果你不喜欢使用原始SQL可以使用阿雷尔方法，例如：
OnlineCourseRegistration.where(course_class_id: 681, status: "Completed").where(OnlineCourseRegistration.arel_table[:score].gt(70)).last
答
为后人我想补充这些cast solutions作为答案也是：
where("score::int >= ?", 80) # PostgreSQL-specific casting syntax
where("cast(score as int) >= ?", 80) # Standard SQL type cast
https://apidock.com/rails/ActiveRec ord/QueryMethods /其中 – krishnar