>What is wrong with this? It replaces all the dates in covr with the same one, probably the first one in the patient table. I can do this in multiple lines with RELATION, but I need it to be one line.

Use UPDATE FROM

>

update covr set covr.ph_dob = patient.ptdob from Covr INNER 
JOIN Patient ON ALLTRIM(covr.pat_no) = ALLTRIM(patient.ptpn)

Also do we need ALLTRIM() ?

Recent thread with the similar question on another forum

http://tek-tips.com/viewthread.cfm?qid=1496541