[This article was copied from the Voyager Wiki.]

This blob query will give you a report of all bib records and their associated 650 fields.  It dumps all output into a table called "650cleanup".  You can keep this file name or change it to suite your purposes.  You can also modify this blob to gather information from any field in the MARC record you want. When viewing the table you will need to expand the depth of the columns so you can view all subject headings gathered.  In default view you can only see the first line.  By expanding the line height you will be able to view each subject heading collected for an individual bib record.

SELECT GetFieldAll(GetBibBlob([BIB_ID]),"650") AS FLDDATA, BIB_TEXT.BIB_ID INTO 650fieldCleanUp
FROM BIB_TEXT
WHERE (((GetFieldAll(GetBibBlob([BIB_ID]),"650"))<>""));