SelectWithUnionQuery (children 2)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Literal UInt64_1000000000 (alias a)
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.numbers
   Literal UInt64_2
 Identifier Pretty
