实现mysql的三表联查

这几天都在学mysql，中午被一道题卡住了

题为：实现goods表,category表,brand表,3表连接查询,得出以下字段

goods_id

cat_id

cat_name

brand_id

brand_name

goods_name

     里面有goods、category、brand三张表，两表联查是会的

<span style="font-family:'Microsoft YaHei';font-size:12px;">select goods_id,goods.cat_id,cat_name,goods.brand_id,goods_name from goods left join category on goods.cat_id = category.cat_id</span>

     可是三表联查却有些绕了，刚开始按我的理解模式为，上面的查询结果当做一张表，再左连接

<span style="font-family:'Microsoft YaHei';font-size:12px;">select goods_id,goods.cat_id,cat_name,goods.brand_id,brand_name,goods_name from goods left join category on goods.cat_id = category.cat_id left join brand on goods.brand_id = brand.brand_id;</span>

         结果是出来了，可是感觉如昨天看的资料有点不一样，昨天是把查询结果当做一张表，然后用括号括起来，再做左连接可发现不成功

<span style="font-family:'Microsoft YaHei';font-size:12px;">select brand_name from (select goods_id,goods.cat_id,cat_name,goods.brand_id,goods_name from goods left join category on goods.cat_id = category.cat_id) as temp left join brand on goods.brand_id = brand.brand_id;</span>

      后来仔细想想，发现应该把

<span style="font-family:'Microsoft YaHei';font-size:12px;">goods left join category on goods.cat_id = category.cat_id</span>

        当做一张表来看，那么结果就可以理解通顺了。

     之所以写这个，一是提醒下自己以后不要又陷入思维定式了，二是，今天中午也上网查了下资料，可是满意的却没有，于是就整理下，写了下来，高手勿哂。