Unanswered: Reporting with Excel: the magic function
This function (SUMPRODUCT) ignored by many is the function that makes Excel the best reporting tool. It allows the user to transform any database extract into a report. With it you can sum a column (amounts) based on ANY number of criteria located in other columns (account, city, product,...). I am a full time Excel-VBA Online Consultant and I use it in 75% of the applications that I develop (even the ones with VBA). It is simple to use yet one of the most powerful function in Excel.
I would not call myself an expert if I didn't know about SUMPRODUCT.
He's been enthusiastically trumpeting his virtues in a thread in the SQL Server forum too.
I am not trumpeting MY virtues but the virtues of SUMPRODUCT. It is a truely amazing function to transform data into information and not many books talk about it. 99% of the people I deal with don't know about this function but after I show them its potential they start using it profusely. It is so friendly that they can start developing great management tools and get rid of their consultant including me. And when this happens, I feel that I have done my job.
The point of these forums are for people to post obstacles they have run into and to post known solutions to these obstacles.
When a user posts something that isn't a question, but proposes the virtue of a formula and then posts a link to their website touting how well they use the formula, well it just smells of advertising and self-promotion. I can't speak for others, but I don't want to go to a forum when I'm looking to be helpful and to look for help, but instead find self-promotion and advertisements. I can go to Google/Yahoo/Lycos/MSN/etc for that.