We have found (much too late!), several thousand instances of 6xx Authority fields with valid $a but missing the $9 (RLIN); I would sincerely appreciate assistance in correcting this. The $a fields are very repetitive, only about twenty in total; to do this "by hand" in the staff interface is "easy" but would be nearly three weeks work at say one minute per record. To do this (obviously starting in the sandbox) by manipulating the MySQL db (biblioitems.marc and biblioitems.marcxml might be the way to go, but I have no experience UPDATEing into longblobs and longtexts. So, (a) is there an easier way? Or (b) Has anyone got a pre-built MySQL script for UPDATEing into long blobs and text? Many thanks for any suggestions. Best - Paul P.S. I've tried along the lines of: UPDATE biblioitems (marc, '//datafield[@tag="650"]/subfield[@code="9"]') = 12345 WHERE(marc, '//datafield[@tag="650"]/subfield[@code="a"]') = 'Authority in question' AND (marc, '//datafield[@tag="650"]/subfield[@code="9"]') IS NULL; but UPDATE seems to fail for marc and marcxml (longtext and longblob), and of course INSERT will not take a WHERE argument. I can't find the field structures in SchemaSpy -- but even with them, I'm not certain that I'm on the right track.