Guides/ReportDesign/15.0-Expressions-in-Izenda.md
... ...
@@ -18,6 +18,8 @@ An expression cannot be run on another expression. Since there can only be one
18 18
19 19
An expression may output a value which is not the expected value for that field's data type. For example, we could use datediff() to calculate an integer number of days on a datetime column, leading Izenda to treat the integer value as a datetime. It is best practice to select a 'container' field that matches your expected output, to prevent unexpected behavior in the report designer.
20 20
21
+*Note*: If you intend for this output to be used in a chart, you _must_ apply an aggregate function to this field. Click [here](http://wiki.izenda.us/FAQ/Calculated-Field-With-Expression-In-Chart) for more details.
22
+
21 23
22 24
**Expressions can:**
23 25