Hi Toshii,
The only options for a memo field is to display it. No formulas, etc, can be written for it - to sort, select, etc.
Not a very handy field! Some people chop this field up at the database level into many fields - all less than 255 chars therefore making them string fields - then concatinate them back together in the report - thereby allowing you to sort on string field #1 - etc.
I hope this answers your question!
Cheers,
paulmarr