MyBatis返回多表连接结果

 

假设我有三个表：Order、Client、Product。
Order表中有列：client_id、product_id，外键分别是Client.id、Product.id
现在我要连接这三个表，返回数据：

OrderMapper.xml:

<select id="selectOrderInfoByOrderId" parameterType="java.lang.Integer" resultType="java.util.Map">
	select `order`.id as order_id,products.name as product_name,`order`.quantity as quantity,
               `order`.last_time as last_time,client.id as client_id,client.name as client_name,client.address as address,client.type as client_type,status
	from `order`
		join products
			on product_id = products.id
		join client
			on client_id = client.id
	where `order`.id = #{id,jdbcType=INTEGER}
</select>

 

OrderDao中实现：

Map<String,Object> selectOrderInfoByOrderId(Integer id);

• 1

注意这是单项查询，如果查询结果有多个行怎么办？比如：

<select id="selectOrderInfo" resultType="java.util.Map">
	select `order`.id as order_id,products.name as product_name,`order`.quantity as quantity,
               `order`.last_time as last_time,client.id as client_id,client.name as client_name,client.address as address,client.type as client_type,status
	from `order`
		join products
			on product_id = products.id
		join client
			on client_id = client.id
</select>

 

OrderDao中实现：

List<Map<String,Object>> selectOrderInfo();