Converting Drupal 7 Text Fields to Text Areas

Due to a problem with the CK Editor module not working on text fields, tonight I had to switch some text fields to text areas (change the field type from text to long text).

I didn’t want a module with some update queries, and I didn’t want to do it in drush. I just wanted raw queries. Since I had some trouble finding something to work from (though this Stack Exchange post was pretty good), I thought I’d write it up.

This assumes you’re changing two fields, a and b, which are currently text fields of length 4096.