diff --git a/app/controllers/colleges_controller.rb b/app/controllers/colleges_controller.rb
index ad831e78..418015fd 100644
--- a/app/controllers/colleges_controller.rb
+++ b/app/controllers/colleges_controller.rb
@@ -50,8 +50,7 @@ class CollegesController < ApplicationController
     # Redo：这样做内存会卡死的
     # user_ids = User.find_by_sql("SELECT users.id FROM users LEFT JOIN user_extensions ON users.id=user_extensions.user_id WHERE user_extensions.`school_id` = #{@school.id}").map(&:id)
     # Redo：是否直接使用count会更好
-    all_course_ids = Course.joins("join users u on courses.tea_id = u.id").joins("join user_extensions ue on u.id = ue.user_id").
-        where("courses.id != 1309 and courses.is_delete = 0 and ue.school_id = #{@school.id}")
+    all_course_ids = Course.where("id != 1309 and is_delete = 0 and school_id = #{@school.id}")
     @courses_count = all_course_ids.size
 
     # Redo：对于量比较大的尽量不使用笛卡尔积
@@ -132,7 +131,7 @@ class CollegesController < ApplicationController
                (select count(m.id) from messages m inner join boards b on  b.id=m.board_id and b.parent_id=0 where b.course_id=c.id group by c.id) as messages_count,
                c.tea_id, c.name, c.is_end,
                (SELECT MAX(created_at) FROM `course_activities` ca WHERE ca.course_id = c.id) AS update_time
-               FROM `courses` c join user_extensions ue on ue.user_id = c.tea_id WHERE (ue.school_id = #{@school.id} and c.is_delete = 0)")
+               FROM `courses` c WHERE c.school_id = #{@school.id} and c.is_delete = 0")
 
     @courses.each do |course|
       course[:evaluating_count] = Output.find_by_sql("select sum(g.evaluate_count) as evaluating_count from games g inner join
diff --git a/db/migrate/20190528013018_migrate_course_school_id.rb b/db/migrate/20190528013018_migrate_course_school_id.rb
new file mode 100644
index 00000000..b0669591
--- /dev/null
+++ b/db/migrate/20190528013018_migrate_course_school_id.rb
@@ -0,0 +1,11 @@
+class MigrateCourseSchoolId < ActiveRecord::Migration
+  def up
+    courses = Course.includes(teacher: :user_extensions).where("courses.school_id != user_extensions.school_id or courses.school_id is null")
+    courses.each do |course|
+      course.update_column('school_id', course.teacher.try(:user_extensions).try(:school_id))
+    end
+  end
+
+  def down
+  end
+end