# `countby`

## Description

The `countby` command generates a count for each distinct value in a given expression, effectively grouping the results by that key.

Note

Unlike `count`, which tallies all records in a set, `countby` provides a per-group count based on the specified key or expression.

## Syntax

```dataprime
countby <expression> [as <alias>] [into <keypath>] [(asc|desc)]
```

## Example

**Use case: Count requests by HTTP status code**

When analyzing logs, it's often useful to understand the distribution of response types. The `countby` command groups documents by `status_code` and counts the number of requests in each group.

### Example data

```json
{ "status_code": 200, "path": "/home" },
{ "status_code": 200, "path": "/about" },
{ "status_code": 404, "path": "/missing" },
{ "status_code": 500, "path": "/checkout" }
```

### Example query

```dataprime
countby status_code into request_count asc
```

### Example output

| status_code | request_count |
| ----------- | ------------- |
| 404         | 1             |
| 500         | 1             |
| 200         | 2             |

The `countby` command produces one record per unique status code, with a count of how many times each appears. Using `asc` orders the results from the smallest count to the largest.