create or alter procedure sp_agg_ored as begin end;
create or alter procedure sp_agg_btwn as begin end;
recreate view v_ts_agg as select 0 x, 0 cnt from rdb$database;
commit;
recreate table ts(id int primary key using index ts_pk, x int);
create index ts_x on ts(x);

recreate view v_ts_agg as select x, count(*) cnt from ts group by x;
commit;

insert into ts select row_number()over(), rand()*100 from rdb$types, rdb$types, (select 1 i from rdb$types rows 5);
commit;

set term ^;
create or alter procedure sp_agg_ored( a_selected_x int ) as
  declare n int;
begin
  select count(*) from v_ts_agg v 
  where  
    -- в релизнотах к ФБ-3.0 обещано, что будет всё равно юзать индекс... 
    v.x =:a_selected_x or :a_selected_x is null 
  into n;
end
^

create or alter procedure sp_agg_btwn( a_selected_x int ) as
  declare n int;
begin
  select count(*) from v_ts_agg v
  where v.x
      -- старый изврат-с... но чаще всего - работает Ok :) 
     between coalesce(:a_selected_x, -999999999 ) and coalesce(:a_selected_x, 999999999 ) 
  into n;
end
^
set term ;^
commit;

2014-04-23T15:46:00.7100 (18178:0x7fe179cd9280) EXECUTE_PROCEDURE_FINISH
        /var/db/fb30/oltp30.fdb (ATT_18520, SYSDBA:NONE, NONE, TCPv4:192.168.43.96)
        C:\MIX\firebird\fb25\bin\isql.exe:2652
                (TRA_19676651, CONCURRENCY | WAIT | READ_WRITE)

Procedure SP_AGG_ORED:
param0 = integer, "1"

    835 ms, 945317 fetch(es)

Table                             Natural     Index    Update    Insert    Delete  
***********************************************************************************
TS                                           315005

2014-04-23T15:46:11.0110 (18178:0x7fe179cd9280) EXECUTE_PROCEDURE_FINISH
        /var/db/fb30/oltp30.fdb (ATT_18520, SYSDBA:NONE, NONE, TCPv4:192.168.43.96
        C:\MIX\firebird\fb25\bin\isql.exe:2652
                (TRA_19676651, CONCURRENCY | WAIT | READ_WRITE)

Procedure SP_AGG_BTWN:
param0 = integer, "1"

     10 ms, 9432 fetch(es)

Table                             Natural     Index    Update    Insert    Delete 
**********************************************************************************
TS                                             3142