anchor.diff:  
   @export
   (defun execute (statement)
  -  (execute-with-connection *connection* statement))
  +  (execute-with-connection *connection* statement)
  +  (values))
  
positive.code:       (let ((sxql:*quote-character* (or sxql:*quote-character*
                                          (connection-quote-character *connection*))))
          (sxql:yield statement))
      (when *trace-sql*
        (let ((stack (get-prev-stack)))
          (log:trace :logger *sql-logger*
                     "~A (~{~S~^, ~})~:[~;~:* | ~S~]" sql params stack)))
      (let ((prepared (dbi:prepare conn sql)))
        (apply #'dbi:execute prepared params))))
  
  @export
  (defun retrieve-one (statement &key by = (as *default-row-type*) (prettify t))
  
negative.code: @export
  (defun retrieve-all (statement &key (as *default-row-type*) (prettify t))
    (mapcar (lambda (row)
              (convert-row row :as as :prettify prettify))
            (execute-with-connection *connection* statement)))
  
  @export
  (defun retrieve-all-values (statement &optional key (prettify t))
  