SingleStoreDB v8.1

SYS_GUID and UUID

Generates and returns a new globally unique identifier (GUID) each time it is called.

Syntax

SYS_GUID()

UUID()

Return Type

SYS_GUID: BINARY(16)

UUID: VARCHAR(36)

Remarks

The value returned will be globally unique
A new value will be produced for each row processed
A new value will be produced for each occurrence of the function in the query syntax
UUID works exactly like SYS_GUID except for the return type
SYG_GUID/UUID cannot be used as a default column value for a sharded table
SYS_GUID/UUID cannot be used in a computed column expression in a table definition

Note

Use INT or BIGINT fields for joining tables if performance is the most important consideration. Joining on BINARY(16) columns works, but is noticeably slower. Use AUTO_INCREMENT, or implement application code to provide integer key values on which to join tables, for the best performance.

Examples

SYS_GUID Example

Create a simple table and insert a row. In order to display the GUID, convert it to HEX:

CREATE TABLE id_t(a INT, b BINARY(16));
INSERT id_t VALUES(1, SYS_GUID());

SELECT a, HEX(b) FROM id_t;
****
+------+----------------------------------+
| a    | HEX(b)                           |
+------+----------------------------------+
|    1 | 7CD5B7769DF95CEFE034080020825436 |
+------+----------------------------------+

UUID Example

CREATE TABLE id_t2(a INT, b VARCHAR(36));
INSERT INTO id_t2 VALUES(1, UUID());

SELECT * FROM id_t2;
****
+------+--------------------------------------+
| a    | b                                    |
+------+--------------------------------------+
|    1 | 15c67225-38f9-483b-8394-02a9e35a9156 |
+------+--------------------------------------+

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