Checking for Orphans

Version: 7.31 OS: AIX 4.3.3 I have a situation whereby I am trying to determine the number of orphans in an addresses table by checking for those address keys NOT IN the five tables which use it, to wit: SELECT count(*) FROM address WHERE addr_key NOT IN (SELECT addr_key FROM client) AND addr_key NOT IN (SELECT addr_key FROM employee) AND addr_key NOT IN (SELECT addr_key FROM groups) AND addr_key NOT IN (SELECT addr_key FROM patient) AND addr_key NOT IN (SELECT addr_key FROM provider) These tables contain anywhere from a few hundred to a few million rows and only the address and patient tables have an index on the addr_key column. After running three hours the query returns a zero count which I know is NOT correct. After pulling hair (and I don't have that much left to pull!), I still cannot see what I am missing. Any ideas? Is there a better way to do this? Thank you, Lucky Lucky Leavell Phone: (800) 481-2393 or (812) 366-4066 UniXpress - Your Source for SCO FAX: (888) 231-9640 or (812) 366-3618 1560 Zoar Church Road NE Email: lucky@UniXpress.com Corydon, IN 47112-7374 WWW Home Page: http://www.UniXpress.com