sql server - Grouping multiple queries on same table , TQSL -

i have rather large table of inormation needs filtered differently several different work departments. created below query returns same number of columns should able union'd up. want make sure no duplicate rows returned, hence reason used union, keep getting error "msg 8120, level 16, state 1, line 53 column 'act_dw.dbo.inv-act.dnum' invalid in select list because not contained in either aggregate function or group clause."
see issue here? looking 1 big table of records grouped deskname field per workgroup if possible.

    declare @inventoryasofeod date,         @start date,         @end date      set @start = cast(dateadd(month, datediff(month, 0, getdate()),0) date) set @end = cast(dateadd(day, -(day(dateadd(month, 1, getdate()))), dateadd(month, 1, getdate())) date)  if     datename(dw, getdate()) = 'monday' begin     set @inventoryasofeod = cast(dateadd(d, -3, getdate())as date)  end else     set @inventoryasofeod = cast(dateadd(d, -1, getdate()) date)  print @inventoryasofeod print @start print @end    select      dnum,     ssn,     dtrfirstname,     dtrlastname,     assigndate,     [desk],     deskname,     pymtamt1,     duedate,     pni,     pibalatsetup,     ttl_balance,     pmgroup,     progtype,     office,     client,     batch,     placetype,     pymtdt1,     ttl_starts   (select      dnum,     ssn,     dtrfirstname,     dtrlastname,     assigndate,     [desk],     deskname,     pymtamt1,     progstartdt duedate,     sum([prinbal]+[intbal]) pni,     pibalatsetup,     balance ttl_balance,     pmgroup,     progtype,     office,     client,     batch,     placetype,     pymtdt1,     count(ssn) ttl_starts       [act_dw].[dbo].[inv-act] with(index([ix_inv-act_inventoryasofeod]),nolock)      inventoryasofeod = @inventoryasofeod ,     bc ='gsl' ,     progtype not in('pmt plan', 'fallout', 'pif', 'sif') ,     progtype not null ,     pymtdt1 between @start , @end   union  --get oregon starts  select      dnum,     ssn,     dtrfirstname,     dtrlastname,     assigndate,     [desk],     deskname,     pymtamt1,     progstartdt duedate,     sum([prinbal]+[intbal]) pni,     pibalatsetup,     balance ttl_balance,     pmgroup,     progtype,     office,     client,     batch,     placetype,     pymtdt1,     count(ssn) ttl_starts       [act_dw].[dbo].[inv-act] with(index([ix_inv-act_inventoryasofeod]),nolock)     inventoryasofeod = @inventoryasofeod ,     client 'ordor%' ,         progtype not in ('null', 'fallout') ,     pymtdt1 between @start , @end   union  --get perkins starts  select      dnum,     ssn,     dtrfirstname,     dtrlastname,     assigndate,     [desk],     deskname,     pymtamt1,     progstartdt duedate,     sum([prinbal]+[intbal]) pni,     pibalatsetup,     balance ttl_balance,     pmgroup,     progtype,     office,     client,     batch,     placetype,     pymtdt1,     count(ssn) ttl_starts     [act_dw].[dbo].[inv-act] with(index([ix_inv-act_inventoryasofeod]),nolock)     inventoryasofeod = @inventoryasofeod ,     bc in ('pe1', 'pe2', 'pe3', 'nu1', 'nu2', 'nds') ,     progtype not in ('null', 'fallout') ,     pymtdt1 between @start , @end  union   --get starts tuition  select      dnum,     ssn,     dtrfirstname,     dtrlastname,     assigndate,     [desk],     deskname,     pymtamt1,     progstartdt duedate,     sum([prinbal]+[intbal]) pni,     pibalatsetup,     balance ttl_balance,     pmgroup,     progtype,     office,     client,     batch,     placetype,     pymtdt1,     count(ssn) ttl_starts     [act_dw].[dbo].[inv-act] with(index([ix_inv-act_inventoryasofeod]),nolock)     inventoryasofeod = @inventoryasofeod ,     bc in ('ar1', 'ar2', 'in1', 'in2', 'in3', 'tu1', 'tu2', 'tu3') ,     progtype not in ('null', 'fallout') ,     pymtdt1 between @start , @end  union   --get starts chase  select      dnum,     ssn,     dtrfirstname,     dtrlastname,     assigndate,     [desk],     deskname,     pymtamt1,     progstartdt duedate,     sum([prinbal]+[intbal]) pni,     pibalatsetup,     balance ttl_balance,     pmgroup,     progtype,     office,     client,     batch,     placetype,     pymtdt1,     count(ssn) ttl_starts     [act_dw].[dbo].[inv-act] with(index([ix_inv-act_inventoryasofeod]),nolock)     inventoryasofeod = @inventoryasofeod ,     client 'ag%' ,     progtype not in ('null', 'fallout') ,     pymtdt1 between @start , @end)      startstable  group      dnum,     ssn,     dtrfirstname,     dtrlastname,     assigndate,     pymtamt1,     duedate,     pibalatsetup,     ttl_balance,     progtype,     desk,     deskname,     pmgroup,     office,     client,     batch,     placetype,     pymtdt1 order      pmgroup,     desk 

you need include group by clause each subquery includes aggregates. instead union rows , then aggregate, different query.