> For the complete documentation index, see [llms.txt](https://docs.cascade.io/cascade/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cascade.io/cascade/functions-and-expressions/functions/aggregate/runningtotalby/zn.md).

# ZN

ZN( `column`)

Fills all null values within a `column` with 0

### Arguments

| Argument | Description                   |
| -------- | ----------------------------- |
| `column` | Column containing null values |

### Output

Returns a column with all null values replaced with 0

### Example

{% embed url="<https://datawrapper.dwcdn.net/NA7Xh/1>" %}