mysql多表关联,根据第一个表中某一个字段的值不同，选择关联不同的表 。解决方案

现有需求：mysql查询特定字段，根据第一个表中某一个字段的值不同，获取不同的表的特定字段值。

发现两种解决方案，如有其他方法，欢迎留言补充，互相交流，共同进步~~

解决方案：

方案一：

$sql1 = "SELECT t1.id,t1.name,t1.add_time,t1.is_adopt,     CASE         WHEN t1.customer_type=2 THEN             (SELECT name FROM company_info as t2 WHERE t2.company_id=t1.customer_id)         WHEN t1.customer_type=3 THEN             (SELECT name FROM factory_info as t2 WHERE t2.factory_id=t1.customer_id)         END AS company_name,     CASE         WHEN t1.customer_type=2 THEN '经销商'         WHEN t1.customer_type=3 THEN '厂商'     END AS company_type FROM brand as t1 order by t1.add_time desc,t1.is_adopt asc;";   方案二： $sql3 = "select d.id,d.name,d.add_time,d.is_adopt,     (case        when d.customer_type = 2 then          a.name        when d.customer_type = 3 then          b.name     end)  AS company_name,     (CASE         WHEN d.customer_type = 2 THEN '经销商'         WHEN d.customer_type = 3 THEN '厂商'     END) AS customer_type from brand as d left join company_info as a on a.company_id=d.customer_id left join factory_info as b on b.factory_id=d.customer_id order by d.add_time desc,d.is_adopt asc;";   总结一下，一种是在查询字段时直接设置子查询；另一种是先设置字段，在后面通过左连接的形式关联表去查询。 两种方法均可实现。  

标签：customer,多表,name,company,t1,mysql,关联,type,id
来源： https://www.cnblogs.com/xccode/p/16055783.html