# hash

## Description

One 128-bit lowercase hexadecimal fingerprint of the result values. It is useful for result comparisons, not cryptographic authentication.

Output only. Select it with `FORMAT hash`. Names ignore ASCII case; use the snake_case name shown here.

The fingerprint covers values in row and column order; column labels do not enter it. Define an ORDER BY when the comparison must use the same row sequence. Native types and NULL markers are significant to the representation.

A nonempty schema with no rows still produces the empty-result fingerprint. Use this format to compare query results, not to authenticate untrusted data.

```text
SELECT expressions FORMAT hash;
```

## Example usage

```sql
SELECT CAST(7 AS Int64) AS id, 'Ada' AS name FORMAT hash;
```

```text
23ac1e3d42ef081779b2184ca4cb3049
```

## Format settings

Use a statement `SETTINGS` clause; these options are not persisted by `SET`.

There are no format-specific settings.