PostgreSQL data duplication problem when sorting pagination

When sorting and paging at the same time, if the sorted field x is not a unique field, the order is random when the X field of multiple records has the same value.

This has the potential to cause duplication of data when paging. A page and the previous page of the data to find out, in fact, the database only one record.

Workaround:

If the sort field is not unique, a level two sort is added, and a field of level two is unique (for example, id).

order by birthday desc, id

PostgreSQL data duplication problem when sorting pagination