Ok, so, I have a lot of articles classified in multiple categories across my site. Let's say I have a category page for Atlanta where it lists all articles classified in Atlanta. In the sidebar, I'd like to show only the categories where there is an article classified as Atlanta AND whatever other category. Does that make sense?
I'm trying to do this without having to write a custom plugin that does this for me. Just am not sure if there is a way
Yeah, you just do this:
category="3&7&8"
http://expressionengine.com/user_guide/modules/channel/parameters.html#par_category
I personally hate EEs categories though. The way I'd do it is to use Playa. This plugin is well worth it. So instead of using EE categories, you create a channel of all your categories (cities). Then you create a playa field in your Articles channel, which allows you to select multiple cities. Then in your template, you just write an if statement:
{if cities="Atlanta && Sheboygan"}//DO SOMETHING{/if}