SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function CAST (alias t) (children 1)
     ExpressionList (children 2)
      Literal \'(1, (\\\'a\\\', \\\'b\\\'))\'
      Literal \'Tuple(c1 UInt64, t1 Tuple(c1 String, c2 String))\'
   ExpressionList (children 3)
    Identifier t.c1
    Identifier t.t1.c1
    Identifier t.t1.c2
