code: private FieldDescriptor getFldFromJoin(TableAlias aTableAlias, String aColName)
      {
          FieldDescriptor fld = null;
  
          // Search Join Structure for attribute
          if (aTableAlias.joins != null)
          {
              Iterator itr = aTableAlias.joins.iterator();
              while (itr.hasNext())
              {
                  Join join = (Join) itr.next();
                  ClassDescriptor cld = join.right.cld;
  
                  if (cld != null)
                  {
                      fld = cld.getFieldDescriptorByName(aColName);
                      if (fld != null)
                      {
                          break;
                      }
  
                  }
              }
          }
          return fld;
      }
docs: Get FieldDescriptor from joined superclass.