Amazon Redshift will no longer support the use of Python UDFs after June 30, 2026. We will start enforcing it in phases. For more information on the details of Python end of life and migration options, see the [ blog post ](https://aws.amazon.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/) that was published on June 30, 2025. 

# Expressions
<a name="r_expressions"></a>

**Topics**
+ [Simple expressions](#r_expressions-simple-expressions)
+ [Compound expressions](r_compound_expressions.md)
+ [Expression lists](r_expression_lists.md)
+ [Scalar subqueries](r_scalar_subqueries.md)
+ [Function expressions](r_function_expressions.md)

An expression is a combination of one or more values, operators, or functions that evaluate to a value. The data type of an expression is generally that of its components. 

## Simple expressions
<a name="r_expressions-simple-expressions"></a>

A simple expression is one of the following: 
+ A constant or literal value 
+ A column name or column reference 
+ A scalar function 
+ An aggregate (set) function 
+ A window function 
+ A scalar subquery 

Examples of simple expressions include: 

```
5+12
dateid
sales.qtysold * 100
sqrt (4)
max (qtysold)
(select max (qtysold) from sales)
```