ID           NAIM
 1             jkl
 2             <null>
 3             <null>
 4              123 
 5             <null>
 6             <null>
 7             <null>
 8             <null>

CREATE PROCEDURE NEW_PROCEDURE 
returns (ttt varchar( 20 ))
as
begin
  ttt = 'Ёпрст';
  for select coalesce(TEST.NAIM, :ttt) as TTT from TEST into :ttt do
  begin
    suspend;
  end
end

TTT
jkl
Ёпрст
Ёпрст
 123 
Ёпрст
Ёпрст
Ёпрст
Ёпрст

FOR SELECT A.QQQ FROM A WHERE A.WWW < :TTT INTO :TTT

create or alter procedure new_procedure
returns (
    ttt varchar( 20 ))
as
  declare c cursor for (select coalesce(test.naim, :ttt) as ttt from test);
begin
  open c;
  while ( 1  =  1 ) do
  begin
    fetch c into :ttt;
    if (row_count =  0 ) then
      leave;
    suspend;
  end
  close c;
end

  for select ttt from (select coalesce(test.naim, :ttt) as ttt from test) into :ttt do
  begin
    suspend;
  end

FOR SELECT A.QQQ FROM A WHERE A.WWW < :TTT INTO :TTT

TID
 1 
 2 
 3 
 4 
 5 
 6 

create or alter procedure new_procedure
returns (
    ttt integer)
as
begin
 ttt =  1 ;
 for select test.aid +  1  as ttt from test where test.aid <= :ttt into :ttt do
 begin
   suspend;
 end
end

TTT
 2 
 3 
 4 
 5 
 6 
 7 

  ttt = 'qqq';
  for select coalesce(test.naim, :ttt) as ttt from test order by test.naim nulls first into :ttt do
  begin
    suspend;
  end

TTT
qqq
qqq
qqq
qqq
 111 
 222 

 ttt =  1 ;
 for select test.aid +  1  as ttt from test where test.aid <= :ttt order by  1  into :ttt do
 begin
   suspend;
 end

TTT
 2