oracle11g - trigger to update value from one table to other -

i'm trying create trigger value of plan_id db table has occured more 3 times , update value of amount regarding plan_id in preplan or postplan tables(wherever plan_id belongs to).

schema tables this:

db table:

 name                                      null?    type  ----------------------------------------- -------- ----------------------------  plan_id                                   not null number  connection_id                             not null number 

preplan:

 name                                      null?    type  ----------------------------------------- -------- ----------------------------  plan_id                                   not null number  amount                                             number 

postplan:

     name                                      null?    type  ----------------------------------------- -------- ----------------------------  plan_id                                   not null number  amount                                             number 

i have written following trigger this:

create or replace  trigger plan_discount_trigger  after insert    on db each row declare     l_planid  number(5);    l_amount  number(5);  begin   select plan_id db l_planid group plan_id having count(:new.plan_id)>3;     if (l_planid>0 , l_planid<6)         select amount l_amount preplan;         update preplan set prepaid.amount = l_amount - (l_amount * 0.1);      elsif (l_planid>9 , l_planid<16)         select amount l_amount postplan;         update postplan set postpaid.amount = l_amount - (l_amount * 0.1);   else         dbms_output.put_line("invalid plan!");      end if; end; 

its giving error:

8/2      pl/sql: sql statement ignored 8/25     pl/sql: ora-00933: sql command not ended 

just explain me error , how solve it???

this needs changed

 select plan_id db l_planid group plan_id having count(:new.plan_id)>3; 

to

select plan_id l_planid db  group plan_id having count(plan_id)>3;