---
title: UUID Data Type reference
meta:
    description: Universally Unique Identifier (UUID).
---

# UUID

A Universally Unique Identifier (UUID) is a 16-byte value used to uniquely identify records. Tinybird supports the UUID data type, which is internally treated as a sequence of 16 random bytes. At the SQL level, UUIDs are represented in the standard 8-4-4-4-12 format.

Tinybird does not validate that inserted UUIDs conform to a particular variant, treating them as generic 16-byte identifiers.

Example UUID value:

```text
61f0c404-5cb3-11e7-907b-a6006ad3dba0
```

The default value for a UUID is an all-zero UUID. This value appears if a record is ingested into a Data Source with a UUID column, but no specific value is provided for that column.

```text
00000000-0000-0000-0000-000000000000
```

UUIDs are sorted by their second half, which can lead to non-intuitive sorting behavior. Therefore, it is generally not recommended to use UUID columns directly as primary keys, sorting keys, or partition keys in your Data Sources if a natural, sequential sort order is desired.

Example of non-intuitive sorting:

```sql
SELECT uuid_column FROM my_data_source ORDER BY uuid_column LIMIT 5
```

Result:

```result
┌─uuid_column──────────────────────────┐
│ 36a0b67c-b74a-4640-803b-e44bb4547e3c │
│ 3a00aeb8-2605-4eec-8215-08c0ecb51112 │
│ 3fda7c49-282e-421a-85ab-c5684ef1d350 │
│ 16ab55a7-45f6-44a8-873c-7a0b44346b3e │
│ e3776711-6359-4f22-878d-bf290d052c85 │
└──────────────────────────────────────┘
```

As a workaround for sorting, you can convert the UUID to a type with a more intuitive sort order, such as `UInt128`.

Example using conversion to UInt128 for sorting:

```sql
SELECT uuid_column FROM my_data_source ORDER BY toUInt128(uuid_column) LIMIT 5
```

Result:

```result
┌─uuid_column──────────────────────────┐
│ 018b81cd-aca1-4e9c-9e56-a84a074dc1a8 │
│ 02380033-c96a-438e-913f-a2c67e341def │
│ 057cf435-7044-456a-893b-9183a4475cea │
│ 0a3c1d4c-f57d-44cc-8567-60cb0c46f76e │
│ 0c15bf1c-8633-4414-a084-7017eead9e41 │
└──────────────────────────────────────┘
```

## Generating UUIDs

You can generate random UUID version 4 values using the `generateUUIDv4()` function. For more details, see the [UUID functions](../functions/uuid-functions) reference.

## Usage examples

### Example 1: Generating a UUID

This example demonstrates how to generate a new UUID within a `SELECT` query.

```sql
SELECT generateUUIDv4() AS new_uuid
```

Result:

```result
┌─new_uuid─────────────────────────────┐
│ 417ddc5d-e556-4d27-95dd-a34d84e46a50 │
└──────────────────────────────────────┘
```

### Example 2: Querying a default UUID

This example shows how a default (all-zero) UUID might appear in a Data Source if a record was ingested without a specified value for the UUID column.

```sql
SELECT uuid_column, some_string_column FROM my_data_source WHERE uuid_column = '00000000-0000-0000-0000-000000000000' LIMIT 2
```

Result:

```result
┌─uuid_column──────────────────────────┬─some_string_column─┐
│ 417ddc5d-e556-4d27-95dd-a34d84e46a50 │ Example 1          │
│ 00000000-0000-0000-0000-000000000000 │ Example 2          │
└──────────────────────────────────────┴────────────────────┘
```

## Restrictions

The UUID data type supports functions that are also applicable to the [String](../data-types/string) data type, such as `min`, `max`, and `count`.

However, UUIDs do not support arithmetic operations (e.g., `abs`) or standard aggregate functions like `sum` and `avg`.