If you specify more than one sort key,the sort key on the left will be the major sort key and the one on the right will be the minor sort key.

Sort Key

A field or set of fields used to determine the order in which data is sorted in a database or data structure.

Major Sort Key

The primary criterion used to organize data or records in order of importance or relevance.

Minor Sort Key

A secondary criterion used in sorting data, which is applied after the primary sort key to further organize the data when primary keys are identical.