diff --git a/db/migrate/20191204030230_migrate_exercise_single_question_score.rb b/db/migrate/20191204030230_migrate_exercise_single_question_score.rb
new file mode 100644
index 000000000..c71fea157
--- /dev/null
+++ b/db/migrate/20191204030230_migrate_exercise_single_question_score.rb
@@ -0,0 +1,27 @@
+class MigrateExerciseSingleQuestionScore < ActiveRecord::Migration[5.2]
+  def change
+    # 删除判断、单选题中生成多条记录，但exercise_choice_id不同的数据
+    sql = %Q(delete from exercise_answers where (exercise_question_id, user_id) in
+            (select * from (select exercise_question_id, user_id from exercise_answers join exercise_questions eq on exercise_question_id = eq.id where eq.question_type in (0, 2) group by exercise_question_id, user_id having count(*) > 1) a)
+            and id not in (select * from (select min(exercise_answers.id) from exercise_answers join exercise_questions eq on exercise_question_id = eq.id where eq.question_type in (0, 2) group by exercise_question_id, user_id having count(*) > 1 order by exercise_answers.id) b))
+    ActiveRecord::Base.connection.execute sql
+
+    # 更新成绩
+    exercise_answers = ExerciseAnswer.joins(:exercise_question).where(score: -1, exercise_questions: {question_type: [0, 2]})
+    exercise_answers.includes(:exercise_choice, exercise_question: :exercise_standard_answers).find_each do |answer|
+
+      question = answer.exercise_question
+      exercise_user = ExerciseUser.find_by(exercise_id: question.exercise_id, user_id: answer.user_id)
+
+      if exercise_user && exercise_user.commit_status == 1
+        user_choice_position = answer.exercise_choice&.choice_position
+        if user_choice_position && (user_choice_position.to_i == question.exercise_standard_answers.take&.exercise_choice_id.to_i)
+          answer.update!(score: question.question_score)
+          score = exercise_user.score + question.question_score
+          objective_score = exercise_user.objective_score + question.question_score
+          exercise_user.update!(score: score, objective_score: objective_score)
+        end
+      end
+    end
+  end
+end