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> Reference material for CITY_HASH function

# CITY_HASH

Takes one or more input parameters of any data type and returns a 64-bit non-cryptographic hash value. `CITY_HASH` uses the CityHash algorithm for string data types, implementation-specific algorithms for other data types, and the CityHash combinator to produce the resulting hash value. If any of the inputs is `NULL`, the result will be `NULL`. See [HASH](/reference-sql/functions-reference/conditional-and-miscellaneous/hash) if `NULL` values should not produce `NULL`.

## Syntax

```sql theme={"theme":{"light":"css-variables","dark":"css-variables"}}
CITY_HASH(<expression>, [, expression [,...]])
```

## Parameters

| Parameter      | Description                                                      | Supported input types |
| :------------- | :--------------------------------------------------------------- | :-------------------- |
| `<expression>` | An expression that returns any data type that Firebolt supports. | Any                   |

## Return type

`BIGINT`

## Examples

<div className="query-window">
  ```
  SELECT CITY_HASH('esimpson', '08-25-2016');
  ```

  | city\_hash <span>long</span> |
  | :--------------------------- |
  | -6509667128195191394         |

  <p><span>Rows: 1</span><span>Execution time: 4.96ms</span></p>
</div>

<div className="query-window">
  ```
  SELECT CITY_HASH(NULL, '08-25-2016');
  ```

  | city\_hash <span>long null</span> |
  | :-------------------------------- |
  | NULL                              |

  <p><span>Rows: 1</span><span>Execution time: 4.65ms</span></p>
</div>