Expressions may be used in various AppSheet features -- Initial Values, App Formulas, Virtual Columns and Column Constraints (Valid_If, Show_If, Required_If) -- to customize app behavior and provide your users with advanced functionality. Expressions in this article align with the **Columns Expressions** in the **Expression Builder **of the **Editor.** The Expression Builder can be found anywhere you are able to enter a formula/expression, noted by a little "flask" symbol next to it. Clicking on the flask will bring up the Expression Builder. The Expression Builder is "context-aware," i.e. it shows you expressions that are relevant to the specific table you are editing. Also included in the builder is an "instant" expression checker, to verify that the expression is valid.

**Expression components**

Use any of the following values as part of an expression:

**Constants**

- Words, Dates, Times. Highlight all values with
**"quotes"**, except for numeric values, e.g.**"Value"**,**"01/01/2016", "12:00:00" for time, "012:00:00" for duration.**

- Numeric values are noted just as they are, e.g
**10**.

**Columns conditions**

Columns Expressions refer to a column to return a value.

**Columns operators**

- Use
**[_THIS]**to refer to the value of the current column (used in Valid_If, Show_If, and Required_If conditions). See Column Constraints.

- Name any column using square brackets around the exact column name:
**[ColumnName]**. When combining a [ColumnName] with another value, put the expression in**(parentheses)**. May be used in any expression; however, when used in the Initial Value feature, it may only refer to a separate table.

**Common and complex expressions**

**Common expressions**

- ([_THIS]>25)

**Complex expressions**

- Pending

**Columns expression patterns and examples**

From the **Expression Builder**, follow the pattern below for a result. See examples for further clarity.

Pattern |
Result |
Example |

[_THIS] | Text | [_THIS] |

[{column_name}] | Number | [Project #] |

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