Flip Boolean Value in Field I have a product with a field that's a boolean value "Contains Gluten" which stores a "1" for yes and a "0" for no, this is stored in the database as field_contains_gluten_value.

The client now wants it to say "Gluten Free" instead.

Rather than change all of my views and product displays to negate, I figure it would be easier to just flip the value in the database.

I am using feeds to import the products from a csv, but the client has edited products now and changed other fields, so I don't want to change it in excel and import over the top for fear of losing his changes.

In the database how do I change all the "0" values to "1" and vice versa? I'm aware this might not qualify as a Drupal question and might be better on stack overflow, but if there is a Drupal solution you are aware of then I'm all ears!
The SQL would be something like:

UPDATE [field table] SET [field column name]=1 WHERE [field column name]=0