SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 2)
         SelectQuery (children 3)
          ExpressionList (children 1)
           Asterisk
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier union_bug
          Function equals (children 1)
           ExpressionList (children 2)
            Identifier Event
            Literal \'A\'
         SelectQuery (children 3)
          ExpressionList (children 2)
           Identifier Event
           Identifier Datetime
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier union_bug
          Function equals (children 1)
           ExpressionList (children 2)
            Identifier Event
            Literal \'B\'
   ExpressionList (children 1)
    OrderByElement (children 1)
     Identifier Datetime
