# min\_by

[Read this page in HTML](https://www.scopedb.io/docs/reference/functions/aggregate/min_by)

Returns a value from the row with the minimum comparison key.

## Syntax

```scopeql
min_by(<value>, <key>)
```

## Arguments

| Argument  | Type                  | Description                                               |
| --------- | --------------------- | --------------------------------------------------------- |
| `<value>` | Any type              | Expression to return from the selected row. May be NULL.  |
| `<key>`   | Any type except `any` | Expression used to select the row. NULL keys are ignored. |

## Returns

Returns the same type as `<value>`. Returns NULL if there is no non-NULL key. If keys tie, any tied row may be selected.

## Examples

### Keep the details of the fastest request

Find the fastest request per service and retain its ID and status together in one object.

```scopeql
VALUES
    ('checkout', 'req-101', 200, 95), ('checkout', 'req-102', 504, 1200),
    ('catalog', 'req-201', 200, 25), ('catalog', 'req-202', 200, 140)
SELECT $0 AS service, $1 AS request_id, $2 AS status, $3 AS latency_ms
GROUP BY service
AGGREGATE min_by({'request_id': request_id, 'status': status}, latency_ms) AS request
ORDER BY service
```

```text
+----------+---------------------------------------+
| service  | request                               |
+----------+---------------------------------------+
| catalog  | {"request_id":"req-201","status":200} |
| checkout | {"request_id":"req-101","status":200} |
+----------+---------------------------------------+
```

### Find the first acquisition channel

Choose the channel on the earliest event for each buyer, even when events arrive out of order.

```scopeql
VALUES
    ('buyer-17', '2026-06-01T10:05:00Z', 'email'),
    ('buyer-17', '2026-06-01T09:00:00Z', 'search'),
    ('buyer-42', '2026-06-01T11:00:00Z', 'referral')
SELECT $0 AS buyer_id, $1::timestamp AS event_time, $2 AS channel
GROUP BY buyer_id
AGGREGATE min_by(channel, event_time) AS first_channel
ORDER BY buyer_id
```

```text
+----------+---------------+
| buyer_id | first_channel |
+----------+---------------+
| buyer-17 | search        |
| buyer-42 | referral      |
+----------+---------------+
```