Access 2010: The Missing Manual

Grouping

Grouping is an indispensable tool for making sense of large volumes of data by arranging them into smaller groups. You can then perform calculations on each individual group. Consider a list of orders in the Boutique Fudge company. Depending on how you want to group your data, you can consider whether chocolate milk outsells chocolate beer, whether customers in New York crave more cocoa than those in Alabama, and so on.

Figure 11-17. Top: The expression looks like an ordinary text value in Design view. Bottom: When you preview the report, Access performs the calculation and then shows the result.

Frequently Asked Question: Expression Errors

Why does my expression display #Error when I preview it?

The #Error code indicates, unsurprisingly, that something isn’t quite right with your expression. Access tries to evaluate it, runs into trouble, and shows the error message instead.

You can often get a good indication of the problem by switching back to Design view, and then looking at the offending text box control. Usually, you’ll see a green triangle in the control’s top-left corner to highlight the problem. Select it, and an error icon appears immediately to the left. You can hover over the error icon to see a description of the problem, and click it to see a short menu of possible fixes that you can apply and error checking options that can tell Access to ignore this problem ...