1  with cl as (
  2  select 1 client_id from dual union all
  3  select 2 client_id from dual union all
  4  select 3 client_id from dual )
  5  ,obor as (
  6  select 1 client_ref,'Комр' CLNT_OBOR from dual union all
  7  select 1 client_ref,'Монітор' CLNT_OBOR from dual union all
  8  select 2 client_ref,'Мишь' CLNT_OBOR from dual)
  9  ,RQST as (
 10  select 1 client_ref,'О100' CLNT_RQST from dual union all
 11  select 2 client_ref,'О200' CLNT_RQST from dual union all
 12  select 2 client_ref,'О201' CLNT_RQST from dual)
 13  ,u as (
 14  select 'O' f,client_id,CLNT_OBOR x,rownum r from cl,obor where client_ref(+)=client_id
 15  UNION ALL
 16  select 'R' f,client_id,CLNT_RQST x,rownum r from cl,rqst where client_ref(+)=client_id
 17  )
 18  select
 19   lag(cast(null as number),1,client_id)
 20       over (partition by client_id order by nvl(CLNT_OBOR,CLNT_RQST)) cl_id
 21  ,CLNT_OBOR
 22  ,CLNT_RQST
 23  from u
 24  pivot (max(x) for f in ('O' as CLNT_OBOR,'R' as CLNT_RQST))
 25* order by client_id,nvl(CLNT_OBOR,CLNT_RQST)
SQL> /

     CL_ID CLNT_OB CLNT_RQ
---------- ------- -------
         1 Комр    О100
           Монітор
         2 Мишь    О201
                   О200
         3