code: private boolean isRolledUpColumnAllowedInAgg(SqlIdentifier identifier, SqlValidatorScope scope,
  		SqlCall aggCall, SqlNode parent) {
  		Pair<String, String> pair = findTableColumnPair(identifier, scope);
  
  		if (pair == null) {
  			return true;
  		}
  
  		String tableAlias = pair.left;
  		String columnName = pair.right;
  
  		Table table = findTable(tableAlias);
  		if (table != null) {
  			return table.rolledUpColumnValidInsideAgg(columnName, aggCall, parent,
  				catalogReader.getConfig());
  		}
  		return true;
  	}
docs: Returns true iff the given column is valid inside the given aggCall.