<?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.java2nb.novel.mapper.FrontUserMapper">


    <update id="addUserBalance" >
        update user set account_balance = account_balance + ${amount}
        where id = #{userId}
    </update>


</mapper>