SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Identifier k
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 2)
          ExpressionList (children 1)
           Function toNullable (alias k) (children 1)
            ExpressionList (children 1)
             Function toInt256 (children 1)
              ExpressionList (children 1)
               Literal UInt64_321
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier system.one
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      Subquery (alias t) (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 1)
           Function toInt256 (alias k) (children 1)
            ExpressionList (children 1)
             Literal UInt64_321
     TableJoin (children 1)
      ExpressionList (children 1)
       Identifier k