TSM Server 4.3.1 on windows

I am trying to do an sql query and want to find the file size and number of
files that are *.PST files that were backed up in the last 24 hours.

I can

        select sum(file_size),count(*) from contents where file_name like
"%.PST"

But I don't know how to get it in the last 24 hours.  Any help?

... Thanks ... Jack