From: Warren Young Date: November 11 2009 5:51pm Subject: Re: Testing for NULL in a StoreQueryResult List-Archive: http://lists.mysql.com/plusplus/8765 Message-Id: MIME-Version: 1.0 (Apple Message framework v1076) Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit On Nov 11, 2009, at 10:36 AM, Wolfgang Pausch wrote: > I tried to do a > if (result[n][0] == mysqlpp::null) {... }, however then the compiler > says I > would have a ambiguous overload for operator == Direct equality comparison is only supposed to work when you use the Null template, but the return value of result[n][0] is String, not Null. (We wouldn't want it otherwise, because that would imply that all field values are potentially nullable.) What you want is result[n][0].is_null() > PS: When using kmail before, your spamfilter didn't accept my mail > (tried several times) The list is generously hosted for us by MySQL, Inc., so you'll have to work with their IT people to see what can be done.