UPDATE [Crsissues/MBS-2181Inventory].[Tenant_14].[stockappendixes]
SET    stockdraft_id = (SELECT TOP 1 stockdraftentries.stockdraft_id
                        FROM
              [Crsissues/MBS-2181Inventory].[Tenant_14].stockdraftentries
                        WHERE
[Crsissues/MBS-2181Inventory].[Tenant_14].stockdraftentries.appendix_id
=
        [Crsissues/MBS-2181Inventory].[Tenant_14].[stockappendixes].id
AND [Crsissues/MBS-2181Inventory].[Tenant_14].stockdraftentries.isbooked
    = 0)