CategoryMapper.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.subsidy.mapper.CategoryMapper">

    <!-- 通用查询映射结果 -->
    <resultMap id="BaseResultMap" type="com.subsidy.model.CategoryDO">
        <id column="id" property="id" />
        <result column="create_date" property="createDate" />
        <result column="update_date" property="updateDate" />
        <result column="delete_date" property="deleteDate" />
        <result column="name" property="name" />
    </resultMap>

    <!-- 通用查询结果列 -->
    <sql id="Base_Column_List">
        create_date,
        update_date,
        delete_date,
        id, name
    </sql>

    <select id="queryCourseCategory" parameterType="long" resultType="com.subsidy.model.CategoryDO">
        SELECT
        	t2.*
        FROM
            course_category_mapping t
            LEFT JOIN category t2 ON t.category_id = t2.id
        WHERE
            t.delete_date IS NULL
            AND t2.delete_date IS NULL
            and t.course_id = #{courseId}
    </select>
</mapper>