INSERT INTO user_similarity (user1_id, user2_id, similarity_score) VALUES (#{user1Id}, #{user2Id}, #{similarityScore}) ON DUPLICATE KEY UPDATE similarity_score = #{similarityScore}, update_time = NOW() SELECT * FROM user_similarity WHERE (user1_id = #{user1Id} AND user2_id = #{user2Id}) OR (user1_id = #{user2Id} AND user2_id = #{user1Id}) LIMIT 1 SELECT * FROM user_similarity WHERE user1_id = #{userId} OR user2_id = #{userId} ORDER BY similarity_score DESC LIMIT #{limit}