SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 3)
    Function toStartOfHour (alias dt_h) (children 1)
     ExpressionList (children 1)
      Function toStartOfMinute (children 1)
       ExpressionList (children 1)
        Identifier datetime
    Function uniqHLL12 (children 1)
     ExpressionList (children 1)
      Identifier x_id
    Function uniqHLL12 (children 1)
     ExpressionList (children 1)
      Identifier y_id
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier projection_test
   ExpressionList (children 1)
    Identifier dt_h
   ExpressionList (children 1)
    OrderByElement (children 1)
     Identifier dt_h