[Koha] Regarding the author entered in 700$a tag

Dear Friends I want a simple report in which I want Acc. No., Title, Author, Publisher and Co-Authors I entered the co-authors in 700$a tag but there is no koha mapping in this field, How can I extract value from 700$a tag Can u please send me the sql query for the same - Sahadeo D. Taware Librarian, M.L.I.Sc., NET Thakur College of Science and Commerce Thakur Village, Kandivli(E), Mumbai 400101 Mob. No 9324912816