24SQL

create  or  replace  function f_op (p_n1  number , p_op  varchar2 , p_n2  number )  return  number

as

begin

return  case  when p_op =  '+'  then p_n1 + p_n2

when p_op =  '-'  then p_n1 - p_n2

when p_op =  '*'  then p_n1 * p_n2

when p_op =  '/'  and p_n2<> 0  then p_n1 / p_n2

else  null

end ;

end f_op;

/

create  or  replace  procedure pro_241(p1  number , p2  number , p3  number , p4  number )  as

r_result  number  default  0 ;

begin

for r  in (

with t_num  as

( select  1  id ,p1  as n  from dual

union

select  2  id ,p2  as n  from dual

union

select  3  id ,p3  as n  from dual

union

select  4  id ,p4  as n  from dual),

t_op  as

( select  '+'  as o  from dual

union

select  '-'  as o  from dual

union

select  '*'  as o  from dual

union

select  '/'  as o  from dual)

select  distinct

a.n   as a,

o1.o  as o1,

b.n   as b,

o2.o  as o2,

c.n   as c,

o3.o  as o3,

d.n   as d

from t_num a, t_num b, t_num c, t_num d,

t_op  o1, t_op  o2, t_op  o3

where a.id  not  in (b.id, c.id, d.id)

and b.id  not  in (c.id, d.id)

and c.id <> d.id)  loop

r_result := f_op(f_op(f_op(r.a,r.o1,r.b),r.o2,r.c),r.o3,r.d);

if r_result=12  then

dbms_output.put_line( '((' ||r.a||r.o1||r.b|| ')' ||r.o2||r.c|| ')' ||r.o3||r.d);

end  if ;  --((a b) c) d

r_result := f_op(f_op(r.a,r.o1,r.b),r.o2,f_op(r.c,r.o3,r.d));

if r_result=12  then

dbms_output.put_line( '(' ||r.a||r.o1||r.b|| ')' ||r.o2|| '(' ||r.c||r.o3||r.d|| ')' );

end  if ;  --(a b) (c d)

end  loop ;

end ;

/

set serveroutput on;

exec pro_241( 32 , 13 , 3 , 17 );