SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Identifier a
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 2)
           Function ignore (alias a) (children 1)
            ExpressionList (children 1)
             Subquery (children 1)
              SelectWithUnionQuery (children 1)
               ExpressionList (children 1)
                SelectQuery (children 1)
                 ExpressionList (children 1)
                  Literal UInt64_1
           Identifier a (alias b)
