The select_remove extension adds Sequel::Dataset#select_remove for removing existing selected columns from a dataset. It's not part of Sequel core as it is rarely needed and has some corner cases where it can't work correctly.
You can load this extension into specific datasets:
ds = DB[:table] ds.extension(:select_remove)
Or you can load it into all of a database's datasets, which is probably the desired behavior if you are using this extension:
DB.extension(:select_remove)