SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function CAST (alias t) (children 1)
     ExpressionList (children 2)
      Literal \'(\\\'a\\\', \\\'b\\\')\'
      Literal \'Tuple(c1 String, c2 String)\'
   ExpressionList (children 2)
    Identifier t.c1
    Identifier t.c2
