Calculate new values from existing ones using expressions.
There are several places in the app editor where you can use expressions to affect your app's behavior and provide users with advanced functionality. Several AppSheet features use expressions, including: app formulas, initial values, column constraints, and virtual columns.
AppSheet checks all expressions to ensure they are correctly formed and being used in an appropriate manner. For example, if an expression is being used to assign an initial value to a column of type Number, AppSheet checks that the result of the expression is indeed a Number.
There are several different types of expressions that can be used within the app. When you're writing expressions in the app editor, you can use Expression Assistant to help construct exactly what you need. When editing column definitions, you can use column constraints to control the behavior of the data in each column. You can also use deep links to access other apps and other views from a given column. To learn more, see Expression types.
Note: If you're familiar with spreadsheet formulas in Microsoft Excel or Google Sheets, you'll find AppSheet expressions similar in syntax and meaning.
An expression may be built with any combination of the following:
Constants
- Numbers: any whole numbers (integers) or real (floating-point) numbers, positive or negative.
- Dates and times, enclosed in double quotes. Format dates as
MM/DD/YYYYand times asHH:MM:SS. For example,"12/31/1999"and"10:15:00". See also Date and time expressions. - Text, enclosed in double quotes. For example,
"Wordy words".
Columns
- Use the value of a column by enclosing the column's name in square brackets like this:
[Column]. Then, you can use columns in expressions. - Dereferences are a type of expression that is useful when you have references between tables.Tips and tricks
Watch the following webinar to learn the fundamentals of building expressions.
Note: The concepts in this video are still valid. Though, the AppSheet UI has changed since this video was recorded.
Deep-Dive Webinar: Expressions Part 1
Tips and tricks
Learn tips and tricks for building expressions from the AppSheet Community:
Sample template
Use the Quote Calculator template which shows the use of various expressions in app formula