SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function tupleHammingDistance (children 1)
     ExpressionList (children 2)
      Function tuple (children 1)
       ExpressionList (children 1)
        Literal NULL
      Function tuple (children 1)
       ExpressionList (children 1)
        Literal NULL
