i have a master record, which has several smaller workhistory records associated with it.

so far so good, a parent and child relationship is fine, allready set up in fact.

on each day i want to produce a report of all the work done for a day along with various bits of data from the master record.

i underatand a lookup could return the field i want from the most recent record, but i want all the work records for that day, and i want to concatenate those fields into one string field.

is a portal the only solution or could i get a script or calculation for retrieve the data??

It sounds like you are attempting to report on the workhistory records. Try attacking the problem from the workhistory.fp5 file and get the header (master) info from via a relationship.