generateUUIDv4 #

generate version 4
Syntax

generateUUIDv4()

Return value

• A value of UUID type.

Example
This example demonstrates how to create a table with a UUID type column and insert values into the table.

CREATE TABLE test.functionGenerateUUIDv4 (x UUID) ENGINE=CnchMergeTree ORDER BY x; 
INSERT INTO test.functionGenerateUUIDv4 SELECT generateUUIDv4(); 
SELECT * FROM test.functionGenerateUUIDv4;

┌─x────────────────────────────────────┐ 
│ a630fbcb-1a32-4902-b5cc-dd51eba8cf4b │ 
└──────────────────────────────────────┘

toUUID #

Converts a string type value to a UUID type. If the input string is not a valid UUID format, an exception is raised.
Syntax

toUUID(String)

Parameter

• String— a string in UUID format.

Return value

• A value of UUID type.

Example

SELECT toUUID('61f0c404-5cb3-11e7-907b-a6006ad3dba0') AS uuid, toTypeName(uuid) AS uuid_type;

┌─uuid─────────────────────────────────┬─uuid_type─┐ 
│ 61f0c404-5cb3-11e7-907b-a6006ad3dba0 │ UUID      │ 
└──────────────────────────────────────┴───────────┘

toUUIDOrNull #

It accepts a string type parameter and tries to parse it as a UUID. If it fails, it returns NULL.
Syntax

toUUIDOrNull(String)

Parameter

• String— a string in UUID format.

Return value

• A value of Nullable(UUID) type.

Example

SELECT toUUIDOrNull('61f0c404-5cb3-11e7-907b-a6006ad3dba0T') AS uuid

┌─uuid─┐ 
│ ᴺᵁᴸᴸ │ 
└──────┘

toUUIDOrZero #

It accepts a string type parameter and tries to parse it as a UUID. If it fails, it returns a zero UUID.
Syntax

toUUIDOrZero(String)

Parameter

• String— a string in UUID format.

Return value

• A value of UUID type.

Example

SELECT toUUIDOrZero('61f0c404-5cb3-11e7-907b-a6006ad3dba0T') AS uuid

┌─uuid─────────────────────────────────┐ 
│ 00000000-0000-0000-0000-000000000000 │ 
└──────────────────────────────────────┘