I have "posts" and "comments", and I'd like to display the number of comments each post has (and display 0 if none). In the index Posts view, I display a list of posts and their authors using the below partial. What I can't figure out is how to limit the comment count to the post listing (my attempts so far show the total number of comments in the database). How do I limit the count?
partial:
<% div_for post do %> <p><strong><%= link_to_unless_current h(post.title), post %></strong>
I think, you must have Post-'has many"-Comments relationship
So, to find number of comments: post.comments.count will give you total number of comments of a post.
-Gourav
That did it. I think I've been staring at the monitor too
long... 
Depending on performance needs, you can also look at the counter_cache option for the ActiveRecord association.
Your current approach has to query the child table to get the count, which could be a performance hit on a big site. Don't prematurely optimize though - it's just good to know about other options in case the need arises.