dbms

Syntax:     DECLARE cursor_name [ INSENSITIVE ] [ SCROLL ] CURSOR
    	 FOR select_statement
    	 [ FOR { READ ONLY | UPDATE [ OF column_name [ ,...n ] ] } ]
[;]
Transact-SQL Extended Syntax
DECLARE cursor_name CURSOR [ LOCAL | GLOBAL ]
     [ FORWARD_ONLY | SCROLL ]
     [ STATIC | KEYSET | DYNAMIC | FAST_FORWARD ]
     [ READ_ONLY | SCROLL_LOCKS | OPTIMISTIC ]
     [ TYPE_WARNING ]
     FOR select_statement
     [ FOR UPDATE [ OF column_name [ ,...n ] ] ]
[;]





declare

v_total  elec.total %type;

cursor c is select * from elec;

begin

for i in c loop

if (i.unit <=20) then v_total:=i.rent;

elsif (i.unit<=80) then v_total:= i.rent+(i.unit-40)*.40;

 else

  v_total:= i.rent+(40*.40)+(i.unit-80)*1.40;

 end if;

 update elec set total=v_total  where id=i.id;

 end loop;

end; /