Limitations on Sortable Columns

As of WordPress 3.1 you can add new columns to admin pages and sort them. You could always add them, but being able to sort the columns is new! This was very much welcome from pretty much everyone who makes extra columns, for whatever reason. As someone who likes them (they make sorting so much easier), I pinged out there to ask how it was done?

My Twitter friends bailed me on and found these very helpful links:

These both told you how to add columns to the posts table. But what I wanted to do was add a column to the USERS table. When you see what I wanted to add, I’m sure it’ll be obvious:

  1. Show the DATE someone registered in the users menu
  2. Allow the column to be sortable

Adding in the date was really painless, but I could not, for the life of me, get it to sort! Small problem. Again, I appealed to Twitter, and bless his little black heart, Otto bailed me out and explained to me why that one could work, but others would not.

What I learned

Unless your data in the header is stored in the database, you cannot sort by it. End of story. No further discussion needs to happen. This makes sense, as you cannot sort by dynamically generated content.

Unlike the wp_posts table, you cannot sort by user generated headers in the User Table because of how it draws from the database. Your plugin would have to write to the wp_users table (making new columns instead of using wp_usermeta which is prefered) and even then, the sortables are hard coded. That one broke my head a little. The sortables in the posts table are pluggable (that is, you can make your own). This just isn’t the same becuase WordPress knows what columns are in wp_users. After all, we add stuff to wp_usermeta. This created a circle of ‘Auuuuugh!’ for me.

Thankfully, Otto pointed out that since ‘registered’ is listed for MultiSite, you can leverage that on SingleSite and MultiSite (and also explained why my tweaks worked on MultiSite!).

In the end, I was able to take all that and tweak my “Recently Registered” plugin for WordPress 3.1, and made it look hella cool. If you’re using WordPress MultiSite, you don’t need this at all.

About these ads
StudioPress Theme of the Month
Half-Elf? Try Half OFF WordPress ebooks!