I have a blog with movie critics and I'm using many taxonomies to add some informations about the movies, like director, actors or it's year. Using taxonomies is really useful to display all movies made by the same director (example here).
My only concern is with the release year taxonomy. I'd like to keep this information as a taxonomy, since I can, for instance, have a list of all movies released 10 years ago. I'd like to use this information to sort all other taxonomy archives, since it's almost always more interesting than other sort options. For now, I'm using the name of posts, but it can lead to strange behavior, like here, for the Iron Man saga where movies are not in the right order. If I could sort this list with year of release, it would be much more interesting.
I understood WordPress doesn't want to add taxonomy orderby in queries, and I'd like tu duplicate this taxonomy and add a release date as custom field, since I can sort using a custom field. I made lot of searches and all I could find was the other way (converting a custom field to a taxonomy).
Could you help me adding the date of every posts to a custom field ? I don't know if I should do it with a SQL query (if so, could you tell me what query I should use ?) or with PHP… Or even if I should do something entirely different to resolve my problem…
Thanks for your help !