SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 3)
    Identifier t1.k
    Identifier t1.s
    Identifier t2.x
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (alias t1) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 4)
          ExpressionList (children 2)
           Identifier number (alias k)
           Literal \'a\' (alias s)
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             Function numbers (children 1)
              ExpressionList (children 1)
               Literal UInt64_2
          ExpressionList (children 1)
           Identifier number
          ExpressionList (children 1)
           OrderByElement (children 1)
            Identifier number
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier t2 (alias t2)
     TableJoin (children 1)
      ExpressionList (children 1)
       Identifier k