docs: private String buildFromClause() {
          StringBuilder sqlBuf = new StringBuilder();
  
          sqlBuf.append("FROM ");
  
          String table = null;
          String schema = null;
          for (Enumeration from = mTables.keys(); from.hasMoreElements();) {
              table = (String) from.nextElement();
              /*
                schema = (String) schemas.get(table);
  
                if (schema != null)
                sqlBuf.append(schema + ".");
              */
  
              sqlBuf.append(table);
              sqlBuf.append(from.hasMoreElements() ? ", " : " ");
          }
  
          return sqlBuf.toString();
      }