# `distinct`

## Description

The `distinct` command returns one document per unique value (or combination of values) for the given expressions. It is particularly useful for reporting or identifying unique entities within a dataset.

Functionally, it behaves like a lightweight `groupby` without any aggregation functions—simply collapsing duplicates and returning the first occurrence of each distinct value.

Note

Use `distinct` when you want a list of unique keys, not an aggregate summary.

## Syntax

```dataprime
distinct <expression> [as <alias>] [, <expression_2> [as <alias_2>], ...]
```

## Example

**Use case: Generate a list of unique active users**

Suppose your logs contain multiple entries per user as they interact with your system. You can use `distinct` to produce a clean list of unique usernames for reporting or activity tracking.

### Example data

```json
{ "username": "Chris", "action": "login" },
{ "username": "Chris", "action": "upload" },
{ "username": "Dave", "action": "login" },
{ "username": "Maria", "action": "logout" },
{ "username": "Maria", "action": "login" }
```

### Example query

```dataprime
source logs
| filter username != null
| distinct username as active_users
```

### Example output

| active_users |
| ------------ |
| Chris        |
| Dave         |
| Maria        |

The `distinct` command collapses repeated usernames into a single record for each, creating a clear list of active users.