A universally unique identifier (UUID) is a 16-byte number used to identify records. For detailed information about the UUID, see [Wikipedia](https://en.wikipedia.org/wiki/Universally_unique_identifier).
The UUID data type only supports functions which [String](string.md) data type also supports (for example, [min](../query_language/agg_functions/reference.md#agg_function-min), [max](../query_language/agg_functions/reference.md#agg_function-max), and [count](../query_language/agg_functions/reference.md#agg_function-count)).
The UUID data type is not supported by arithmetic operations (for example, [abs](../query_language/functions/arithmetic_functions.md#arithm_func-abs)) or aggregate functions, such as [sum](../query_language/agg_functions/reference.md#agg_function-sum) and [avg](../query_language/agg_functions/reference.md#agg_function-avg).