SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function in (children 1)
     ExpressionList (children 2)
      Function CAST (children 1)
       ExpressionList (children 2)
        Literal NULL
        Literal \'Nullable(String)\'
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 1)
          ExpressionList (children 1)
           Literal \'abc\'
