jnpf-java-boot-v6x/jnpf-admin/target/classes/mapper/extend/BigDataMapper.xml

<?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="jnpf.mapper.BigDataMapper">

    <select id="maxCode" resultType="Integer">
        SELECT MAX(F_EN_CODE) FROM ext_big_data
    </select>

</mapper>