SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function CAST (alias t) (children 1)
     ExpressionList (children 2)
      Literal \'(1, 2)\'
      Literal \'Tuple(a UInt32, b UInt32)\'
   ExpressionList (children 2)
    Function tupleElement (children 1)
     ExpressionList (children 2)
      Identifier t
      Literal UInt64_1
    Function tupleElement (children 1)
     ExpressionList (children 2)
      Identifier t
      Literal \'b\'