How to get this function working

Question

Dear buddies,
I created a function which should check if a certain code exists in a certain table.
Not sure how to get it done
create or replace function check_code(crs_code in varchar) return integer is
  Result integer;
begin
  if crs_code in (select cod_code from crs_code) then
    result := 1;
  else  
    result := 0;
  end if;
  return(Result);
end check_code;error: Compilation errors for FUNCTION CONV.CHECK_CODE
Error: PLS-00405: subquery not allowed in this context
Line: 6
Text: if crs_code in (select cod_code from crs_code) then
Error: PL/SQL: Statement ignored
Line: 6
Text: if crs_code in (select cod_code from crs_code) then

Answer 1

My guess is that
create or replace function check_code(p_crs_code in varchar) return integer is
  l_Result integer;
begin
  SELECT COUNT(*)
    INTO l_result
    FROM dual
   WHERE EXISTS (
      SELECT 1
        FROM crs_code
      WHERE cod_code = p_crs_code
  return( l_Result);
end check_code;should work but you've provided no table structure, no sample data, and no desired output so it's a bit unclear. Note that it is a really bad idea to have parameter names that match table names. My assumption is that CRS_CODE is both a table and a parameter name in your original function. Otherwise, I'm not sure what your SELECT statement is attempting to do.
Justin