WordPress MU

Trying to do what I thought would be pretty simple.
Wanted to add some conditional code based on the post category to the sidebar.

Code I am using is:

<?php global $category_id;
if ($category_id == 259) {echo 'YYY'; }
else {echo 'NNN'; }; ?>

Does not seem to be working correctly.
Not sure where I am going wrong.
Anyone see what I'm missing?

Not sure that you've actually got anything in your variable $category_id

Try using the is_category() function inside a loop... or in_category()

<?php if (in_category('259')
    echo 'YYY';
else
    echo 'NNN';
?>

http://codex.wordpress.org/Template_Tags/in_category

Thanks Driftless1.

Ended up with a plugin work around.
I think the problem was that it wasn't in the loop.

// closed