---
title: "Computed Columns"
description: "This guide introduces one of Pixeltable's most essential and powerful concepts: computed columns."
url: "https://www.pixeltable.com/notebooks/computed-columns"
updated: "2026-09-03"
---

# Computed Columns

This guide introduces one of Pixeltable's most essential and powerful concepts: computed columns.

- **Type:** Notebook
- **Group:** Tutorials

## What it uses

- **Install:** `pip install pixeltable torch transformers timm`
- **Pixeltable calls:** `huggingface.detr_for_object_detection()`, `vision.bboxes_draw()`, `pxt.create_table()`, `add_computed_column()`, `insert()`

## A look at the code

```python
pop_t.add_computed_column(
    yoy_percent_change=(100 * pop_t.yoy_change / pop_t.pop_2022)
)
```

## Open it

- **Open in Colab:** https://colab.research.google.com/github/pixeltable/pixeltable/blob/release/docs/release/tutorials/computed-columns.ipynb
- **Docs page:** https://docs.pixeltable.com/tutorials/computed-columns
- **Source on GitHub:** https://github.com/pixeltable/pixeltable/blob/release/docs/release/tutorials/computed-columns.ipynb