Beyond (at)SUM. (how to use several 'at' functions in Lotus 1-2-3 and Symphony)

Beyond @ SUM

Software users typically rely on a small set of features for most of their work. A few basic skills go a long way in 1-2-3 and Symphony. Sometimes, however, you run into a problem that can't be solved with basic formulas.

Fortunately, a lot of seemingly complicated operations can be solved quite simply by applying the appropriate @function. 1-2-3 and Symphony provide several types of @functions: statistical, mathematical, financial, database statistical, string, date and time, logical, and special. We presented an extensive survey of @functions in our September Special Report on formulas.

This article presents a small sampling of useful @functions in the context of a simple application. You'll learn about @CHOOSE, @MOD, @DATEVALUE, @IF, and @VLOOKUP. If you've never explored the @functions, observe how these building blocks can be assembled in creative and useful ways.

THE PROBLEM

Let's say you're the owner of Laurie's Lunch and Lodging." You want to build a worksheet model that calculates the total charge for each guest's stay. A number of factors go into that calculation: the guest's arrival day and date, length of stay, and rate status--regular, repeat, or senior citizen. Once you get that information into your spreadsheet, you will have what you need to calculate each guest's bill.

The next step is to decide where to enter the raw data--name, arrival day and date, length of stay, and status--and where to calculate the total charge. Enter the labels as shown in the screen below:

To create the dashed line in row 3, enter a backslash and a hyphen (\-) in cell A3 and copy that cell to range B3..F3. For entering the arrival dates in column B, you have two choices. You can enter the dates as labels by preceding each date with a label-prefix character in a form such as '11/12/89. Or you can enter the dates as values by using the @DATE function.

The @DATE function requires three arguments--year, month, and day--and return a serial number that …