一个customer与多article关联
<resultMap id="customerResultMap" type="Customer">
<id column="c_id" property="id"/>
<result column="c_name" property="name"/>
<result column="c_contact" property="contact"/>
<result column="c_telephone" property="telephone"/>
<result column="c_email" property="email"/>
<!-- property: 指的是集合属性的值, ofType:指的是集合中元素的类型 -->
<collection property="articles" javaType="ArrayList" ofType="Article">
<id column="a_id" property="id"/>
<result column="a_title" property="title"/>
<result column="a_content" property="content"/>
</collection>
</resultMap>
<!-- 根据id查询Customer-->
<select id="getCustomerById" parameterType="int" resultMap="customerResultMap">
SELECT
c.id as c_id,
c.name as c_name,
c.contact as c_contact,
c.telephone as c_telephone,
c.email as c_email,
a.id as a_id,
a.title as a_title,
a.content as a_content
FROM customer c
LEFT OUTER JOIN article a ON c.id = a.customer_id
WHERE c.id = #{id}
</select>