insert into new_table (field1,field2) 
values (IIF(:Something= 1 ,  100  ,  200 ),
        IIF(:Something= 1 , 'value2' , 'value4'))

insert into new_table (field1,field2) 
values (CASE :Something WHEN  1  THEN  100 
                        WHEN  2  THEN  133 
                        WHEN  7  THEN  160 
                        ELSE  199  END,
        CASE :Something WHEN  1  THEN 'о-хо-хо'
                        WHEN  2  THEN 'о-го-го!'
                        WHEN  7  THEN 'э-ге-гей!!'
                        ELSE 'нафик' END)

insert into new_table (field1,field2)
values (COALESCE(NULLIF(CAST(:Something AS INTEGER),  1 )|| 100  ,  200 ),
        COALESCE(NULLIF(CAST(:Something AS INTEGER),  1 )||'value2' , 'value4'))

Field1 = SUBSTRING(NEW.SomeStr FROM  1  FOR  5 ); -- Первые пять символов
Field2 = SUBSTRING(NEW.SomeStr FROM  6  FOR  15 ); -- ещё 15
Field3 = SUBSTRING(NEW.SomeStr FROM  21 ); -- всё, что осталось
IF (NOT EXISTS(SELECT * 
                 FROM OTHER_TABLE 
                WHERE Field1 =:Field1 
                  AND Field2 =:Field2 
                  AND Field3 =:Field3) ) THEN
    INSERT INTO OTHER_TABLE(Field1, Field2, Field3)
    VALUES(:Field1, :Field2, :Field3);

INSERT TO COPY_VIEW(SomeStr) 
SELECT SomeStr 
  FROM SOME_TABLE