Expressions: The Essentials

Calculate new values from existing ones using expressions.

About 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, virtual columns, and deep links.

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.

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/YYYY and times as HH: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.

Build expressions

Learn more about building expressions with AppSheet.          

Use Expression Assistant Learn how build expressions using Expression Assistant in the AppSheet editor.	Expression types Understand the types of expressions you can build.
Column expressions Build column expressions that are dynamically computed to determine the behavior of a specific column when the user tries to enter or change its value. For example, you can use column constraints to control the behavior of the data in each column.	List expressions Build list expressions that are dynamically computed to determine the contents of a list.
AppSheet function list  View all of the AppSheet functions that can be used when building expressions.	Tips and tricks Learn tips and tricks for building expressions from the AppSheet Community: Expression tips and tricks Expressions Q&A

 Deep-dive webinar: Build expressions

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

Sample template

Use the Quote Calculator template which shows the use of various expressions in app formula.