Question

I’ve got a query that looks like this:

select a.title, is.filename
  from articles a
  join article_images ai on ai.article_id = a.article_id
  join images i on i.image_id = ai.image_id
  join image_sizes is on is.image_id = i.image_id
 where is.size_name = '96x96';

So there is an N:N relationship between articles and images, and an N:1 relationship between images and image sizes. This selects the 96×96 image for each article.

Now I want to change this so it selects the 96×96 image, unless the article_id is 42, in which case it selects a different size. Is there a way to do that in one query?

Answer 1

Change to this:

where (a.article_id <> 42 AND is.size_name = '96x96')
   OR (a.article_id = 42 AND is.size_name = 'something different')