查询涉及4个表，内部联接？

Question

I am just developing a PHP aplication, and I need a query which involves 4 tables. tables are like:

news {news_pk, user, description, building_pk}
building {building_pk, area_pk, description}
area {area_pk,state_pk}
states {state_pk, name}

I would like to show results filtered by state name (or what I think is the same state_pk ). I would like to show news from a certain state.

I am not using MySQL so often, but in this app I am doing several queries like this and I am not sure if the inner join is a good solution.

Which query could be the most effective to show only news from a certain state?

Answer 1

It very much depends on what you want to do, inner join might be a good solution if it is what you are looking for. You can seel the difference between joins in this answer: What's the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL JOIN?

Hope it helps! :)

Answer 2

您应该对表的联接使用以下查询：

mysql_query("select a.news_pk,a.user.a.description,a.buiding_pk,b.building_pk,b.area_pk,b.description,c.area_pk,c.state_pk,d.state_pk,d.name from news as a,buiding as b,area as c,states as d where a.buiding_pk=b.building_pk and b.area_pk=c.area_pk and c.state_pk=d.state_pk");