diff --git a/db/migrate/20200214022547_add_index_to_user_id_and_shixun_id_for_shixuns.rb b/db/migrate/20200214022547_add_index_to_user_id_and_shixun_id_for_shixuns.rb
index acca274bd..0321d2c6b 100644
--- a/db/migrate/20200214022547_add_index_to_user_id_and_shixun_id_for_shixuns.rb
+++ b/db/migrate/20200214022547_add_index_to_user_id_and_shixun_id_for_shixuns.rb
@@ -5,6 +5,7 @@ class AddIndexToUserIdAndShixunIdForShixuns < ActiveRecord::Migration[5.2]
     shixun_members.each do |sm|
       s = ShixunMember.where.not(id: sm.id).where(user_id: sm.user_id, shixun_id: sm.shixun_id)
       puts "s: #{s.map{|sm| sm.id}}"
+      s.delete_all
     end
 
     add_index :shixun_members, [:user_id, :shixun_id], unique: true