Try

update agreementitems
    set new_iagreementid = agreements.new_iagreementid
  inner join agreements on agreementitems.iagreementid = agreements.iagreementid

>
>I'm using PostgreSQL and trying to run the following update:
>
>update agreementitems
>set agreementitems.new_iagreementid = agreements.new_iagreementid
>from agreementitems inner join agreements on agreementitems.iagreementid = agreements.iagreementid
>
>however, I get this error:
>
>ERROR: table name "agreementitems" specified more than once
>
>This syntax works in VFP (and I think in SQL Server). Can anyone suggest the syntax that PostgreSQL uses?