postgresql - Syntax error at or near ; -

i have many trigger functions, , there strange error: "syntax error @ or near ;" here code:

create or replace function zajisti_vyplnenost() returns trigger $$ begin   if new.typ_vztahu != 1     return new;   end if;    if new.nad.typ_sj = 1     if new.nad.vrstva.vypln = true     else       raise exception 'totožné stratigrafické jednotky musejí být stejného typu!';   end if;    return new; end; $$ language plpgsql;  create trigger zajisti_vyplnenost before insert or update on s_vztah each row   execute procedure zajisti_vyplnenost(); 

according debugger, error should on line 14 (with end;). tried find might cause problem, function looks others don't trigger errors. looked on documentation function , end syntax in plpgsql, no joy, , semicolon makes error quite google unfriendly.

so part of syntax wrong, , how correct it?

looks forgot 1 end if:

if new.nad.typ_sj = 1   if new.nad.vrstva.vypln = true   else     raise exception 'totožné stratigrafické jednotky musejí být stejného typu!';   end if; end if; 

should correct