多张表联合查询时，多张表中包含相同字段，联合查询后相同的字段将会出现以下效果：
其中state，cid ，csid字段为重复字段，可以看出后面再次查询出的重复字段都加了尾缀1

QQ截图20181220093711.png

解决办法可以将重复字段起别名解决：

QQ截图20181220094051.png

附加查询语句：

select product.csid as pcsid ,product.state as pstate,product.date as pdate,product.market_price,
                product.pdesc,product.pid as ppid,product.pname,product.shop_price,product.stock,
             category_floor.state as cstate ,category_floor.cid as cfcid ,category_floor.cname,category_floor.img,category_floor.state as cfstate ,
                category_second_floor.cid as csfcid ,category_second_floor.csid,category_second_floor.csname,category_second_floor.state as csfstate,
                image.date as imgdate ,image.image_id,image.`name`  ,image.old_name,image.path,image.pid as imgpid ,image.state as imgstate
                
                from category_floor
        left join category_second_floor
        on category_floor.cid = category_second_floor.cid
        left join product
        on category_second_floor.csid = product.csid
        left join image
        on product.pid = image.pid

 select  product.csid ,product.state as pstate,product.date as pdate,product.market_price,
                product.pdesc,product.pid ,product.pname,product.shop_price,product.stock,
                category_floor.state as cstate ,category_floor.cid ,category_floor.cname,category_floor.img,category_floor.state as cfstate ,
                category_second_floor.cid  ,category_second_floor.csid,category_second_floor.csname,category_second_floor.state as csfstate,
                image.date as imgdate ,image.image_id,image.`name`  ,image.old_name,image.path,image.pid ,image.state as imgstate

                from category_floor
                left join category_second_floor
                on category_floor.cid = category_second_floor.cid
                left join product
                on category_second_floor.csid = product.csid
                left join image
                on product.pid = image.pid

select  *
    from category_floor
        left join category_second_floor
        on category_floor.cid = category_second_floor.cid
        left join product
        on category_second_floor.csid = product.csid
        left join image
        on product.pid = image.pid