Amazon Redshift will no longer support the creation of new Python UDFs starting Patch 198. Existing Python UDFs will continue to function until June 30, 2026. For more information, 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/). 

# Conditional expressions
<a name="c_conditional_expressions"></a>

**Topics**
+ [CASE conditional expression](r_CASE_function.md)
+ [DECODE function](r_DECODE_expression.md)
+ [GREATEST and LEAST functions](r_GREATEST_LEAST.md)
+ [NVL and COALESCE functions](r_NVL_function.md)
+ [NVL2 function](r_NVL2.md)
+ [NULLIF function](r_NULLIF_function.md)

Amazon Redshift supports some conditional expressions that are extensions to the SQL standard.