# || (string concatenation)

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Concatenates strings with the `||` operator.

## Syntax

```scopeql
<left> || <right> [|| <next> ...]
```

## Arguments

| Argument  | Type     | Description                  |
| --------- | -------- | ---------------------------- |
| `<left>`  | `string` | First string.                |
| `<right>` | `string` | String to append.            |
| `<next>`  | `string` | Optional additional strings. |

## Returns

Returns `string`. Returns NULL if any input is NULL.

## Examples

Combine the service and event name into a label for a report or investigation.

```scopeql
VALUES ('checkout', 'payment_failed'), ('catalog', 'item_viewed')
SELECT $0 AS service, $1 AS event
SELECT service || ': ' || event AS label
```

```text
+--------------------------+
| label                    |
+--------------------------+
| checkout: payment_failed |
| catalog: item_viewed     |
+--------------------------+
```