api/target/classes/mapper/dataexpert/DataExpertSourceMapper.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="com.xjrsoft.module.dataexpert.mapper.DataExpertSourceMapper">
    <select id="getSourceTypeList"  resultType="java.lang.String">
        SELECT DISTINCT data_group FROM data_expert_source_field WHERE delete_mark = 0
    </select>
</mapper>