Hi,
I have a table that shows the people who have barrowed a book :
book_id user_id date_barrowed date_returned
16 340 01/05/1998 05/05/1998
16 340 20/02/2007 25/02/2007
17 340 01/05/1998 05/10/1998
17 450 04/12/1998
23 500 20/02/2007 25/02/2007
65 510 18/03/2008
76 7540 05/07/2008 10/07/2008
How can I query those who have presently barrowed a book that they have already barrowed before ?
Thank you.