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/). 

# Null condition
<a name="r_null_condition"></a>

The null condition tests for nulls, when a value is missing or unknown. 

## Syntax
<a name="r_null_condition-synopsis"></a>

```
expression IS [ NOT ] NULL
```

## Arguments
<a name="r_null_condition-arguments"></a>

 *expression*   
Any expression such as a column. 

IS NULL   
Is true when the expression's value is null and false when it has a value. 

 IS NOT NULL   
Is false when the expression's value is null and true when it has a value. 

## Example
<a name="r_null_condition-example"></a>

This example indicates how many times the SALES table contains null in the QTYSOLD field: 

```
select count(*) from sales
where qtysold is null;
count
-------
0
(1 row)
```