How to sort and filter documents in SharePoint
As
well as using the search to find particular files within a Library, you can
sort and filter a Library in much the same way that you sort and filter in
Microsoft Excel.

You
can sort by the name in Ascending or Descending order. Every other column will
have the same A-Z or Z-A sort feature but beneath that will also have a filter
selection.
This
is automatically populated by SharePoint dependent upon what has been entered
into the columns. If there are 33 entries from the HR dept. then you will only
be offered the check-box for it once in the filter list to choose from.
In
the diagram above there were five items from HR, but HR is only offered once.
If you only want to quickly sort and don’t want to be offered the Filter
options as well, click on the column name rather than the pull-down by the side
of it.