create table tempdb.test( STREETCODE smallint ,LOCATIONHOUSE varchar( 50 ),LOCATIONAPP varchar( 50 ), ltr char( 1 ))

;
insert into tempdb.test values( 1 , 'house1', 'location1', 'A')
, ( 1 , 'house 1', 'location 1', 'B')
, ( 2 , 'house   1', 'location   1', 'C')
, ( 2 , 'house     1', 'location     1', 'D')
, ( 3 , 'house       1', 'location      1', 'E')

;

create procedure tempdb.test_p
begin
declare SQLSTATE char( 5 ) default '00000';
declare v_STREETCODE smallint;
declare v_LOCATIONHOUSE varchar( 50 );
declare v_LOCATIONAPP varchar( 50 );
declare v_ltr char( 1 );
declare cur1 cursor with return to client for
with del(STREETCODE, LOCATIONHOUSE, LOCATIONAPP, ltr )
as (select STREETCODE, LOCATIONHOUSE, LOCATIONAPP, ltr from old table 
    ( delete from tempdb.test  ) ) 
select STREETCODE, replace(LOCATIONHOUSE, ' ',''), replace(LOCATIONAPP, ' ',''), min(ltr) as ltr 
from del 
group by  STREETCODE, replace(LOCATIONHOUSE, ' ',''), replace(LOCATIONAPP, ' ','');

open cur1;
   fetch from cur1 into  v_STREETCODE, v_LOCATIONHOUSE, v_LOCATIONAPP, v_ltr;

     while (SQLSTATE = '00000') do
        insert into tempdb.test
        values (v_STREETCODE, v_LOCATIONHOUSE, v_LOCATIONAPP, v_ltr);
       
        fetch from cur1 into  v_STREETCODE, v_LOCATIONHOUSE, v_LOCATIONAPP, v_ltr; 
     end while;

close cur1;
end

select * from tempdb.test 
потом  call tempdb.test_p()
и потом select * from tempdb.test