优化代码

src/main/resources/mapper/InterviewService.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
+<mapper namespace="com.qingqiu.interview.mapper.InterviewMessageMapper">
+
+    <select id="selectBySessionIdOrderByOrder" resultType="com.qingqiu.interview.entity.InterviewMessage">
+        SELECT * FROM interview_message 
+        WHERE session_id = #{sessionId}
+        ORDER BY message_order ASC
+    </select>
+
+    <select id="selectLatestBySessionId" resultType="com.qingqiu.interview.entity.InterviewMessage">
+        SELECT * FROM interview_message 
+        WHERE session_id = #{sessionId}
+        ORDER BY message_order DESC
+        LIMIT 1
+    </select>
+
+    <select id="selectMaxOrderBySessionId" resultType="int">
+        SELECT COALESCE(MAX(message_order), 0) FROM interview_message 
+        WHERE session_id = #{sessionId}
+    </select>
+
+</mapper>