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  • 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();
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  • 原文地址:https://www.cnblogs.com/shoshana-kong/p/14274801.html
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