MacLochlainns Weblog

I’ve worked with every release of Microsoft Excel, and I know it takes effort to keep up to date with certain releases. Clearly, the Data Analysis eXpression (DAX) Language introduced in Excel 2010 went unnoticed by many, which was sad. DAX is truly a powerful extension to the analytical and modeling approaches in Microsoft Excel.

I’d like to recommend Microsoft Excel 2013 Building Data Models with PowerPivot to those who haven’t learned how to use DAX in Excel 2010, 2011, or 2013. DAX works with tables but if you don’t use tables, I guess you can skip DAX because you must have infinite time to produce marginal analytical outcomes (tongue in cheek humor). However, if you’re like most folks, you want a book to get you up-to-speed quickly, and that’s what this book will do for you.

Just one caveat if you’re using an Oracle or MySQL database, use the prepackaged analytic functions before you download the data set. You should always pre-select data before applying analytics in Excel. Remember the more refined the data model you start with the easier it is to structure analytical tools to leverage the data model. While DAX is powerful, it doesn’t replace the speed and query optimized behaviors of effective Oracle or MySQL queries.

I had an interesting reaction when I told my students they had to create a dynamic Excel model that required them to enter the months of the year without AutoFill feature. They were stumped. They couldn’t find a function to perform it for them.

It’s really quite easy, the EDATE function lets you find it directly. Enter any day in the current month as the first parameter and one as the number of months to add as the second parameter to the function. Voilà, you have a function to add a month to any date. The only time it returns the first of the next month is when the source date was the first day of the current month.

Here’s the solution when cell B1 contains January 14, 2011 and you want cell C1 calculated as the fourteenth day of February in the same year or February 14, 2011:

=EDATE(B1,1)

Here’s the solution when cell B1 contains January 14, 2011 and you want cell C1 calculated as the fourteenth day of December in the prior year or December 14, 2010:

=EDATE(B1,-1)

You can also use the EOMONTH function to find the first or last day of the month. It lets you find it the first day of the next month regardless of the start date. All you need is a simple trick.

Enter any day in the current month as the first parameter and zero as the number of months to add as the second parameter to the function, and then add one.

Here’s the solution when cell B1 contains any day in January and you want cell C1 calculated as the last day of January in the same year (rounding up).

=EOMONTH(B1,0)

Here’s the solution when cell B1 contains any day in January and you want cell C1 calculated as the first day of January in the same year (rounding down).

=EOMONTH(B1,-1)+1

A subsequent question asked how to calculate the 15th day of the current month, and here’s the formula:

=EOMONTH("10-Jul-2012",-1)+15

Hope this helps them and others looking for the trick.