How to check if a string is a uniqueidentifier?

Is there an equivalent to IsDate or IsNumeric for uniqueidentifier (SQL Server)? Or is there anything equivalent to (C#) TryParse?

Otherwise I'll have to write my own function, but I want to make sure I'm not reinventing the wheel.

The scenario I'm trying to cover is the following:

SELECT something FROM table WHERE IsUniqueidentifier(column) = 1
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I am not aware of anything that you could use "out of the box" - you'll have to write this on your own, I'm afraid.

If you can: try to write this inside a C# library and deploy it into SQL Server as a SQL-CLR assembly - then you could use things like Guid.TryParse() which is certainly much easier to use than anything in T-SQL....

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You can write your own UDF. This is a simple approximation to avoid the use of a SQL-CLR assembly.

CREATE FUNCTION dbo.isuniqueidentifier (@ui varchar(50))
RETURNS bit AS
BEGIN


RETURN case when
substring(@ui,9,1)='-' and
substring(@ui,14,1)='-' and
substring(@ui,19,1)='-' and
substring(@ui,24,1)='-' and
len(@ui) = 36 then 1 else 0 end


END
GO

You can then improve it to check if it´s just about HEX values.

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SELECT something
FROM table1
WHERE column1 LIKE '[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]-[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]-[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]-[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]-[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]';

UPDATE:

...but I much prefer the approach in the answer by @r0d30b0y:

SELECT something
FROM table1
WHERE column1 LIKE REPLACE('00000000-0000-0000-0000-000000000000', '0', '[0-9a-fA-F]');
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Not mine, found this online... thought i'd share.

SELECT 1 WHERE @StringToCompare LIKE
REPLACE('00000000-0000-0000-0000-000000000000', '0', '[0-9a-fA-F]');
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最佳答案

SQL Server 2012 makes this all much easier with TRY_CONVERT(UNIQUEIDENTIFIER, expression)

SELECT something
FROM   your_table
WHERE  TRY_CONVERT(UNIQUEIDENTIFIER, your_column) IS NOT NULL;

For prior versions of SQL Server, the existing answers miss a few points that mean they may either not match strings that SQL Server will in fact cast to UNIQUEIDENTIFIER without complaint or may still end up causing invalid cast errors.

SQL Server accepts GUIDs either wrapped in {} or without this.

Additionally it ignores extraneous characters at the end of the string. Both SELECT CAST('{5D944516-98E6-44C5-849F-9C277833C01B}ssssssssss' as uniqueidentifier) and SELECT CAST('5D944516-98E6-44C5-849F-9C277833C01BXXXXXXXXXXXXXXXXXXXXXXXXXXXXX' as uniqueidentifier) succeed for instance.

Under most default collations the LIKE '[a-zA-Z0-9]' will end up matching characters such as À or Ë

Finally if casting rows in a result to uniqueidentifier it is important to put the cast attempt in a case expression as the cast may occur before the rows are filtered by the WHERE.

So (borrowing @r0d30b0y's idea) a slightly more robust version might be

;WITH T(C)
AS (SELECT '5D944516-98E6-44C5-849F-9C277833C01B'
UNION ALL
SELECT '{5D944516-98E6-44C5-849F-9C277833C01B}'
UNION ALL
SELECT '5D944516-98E6-44C5-849F-9C277833C01BXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
UNION ALL
SELECT '{5D944516-98E6-44C5-849F-9C277833C01B}ssssssssss'
UNION ALL
SELECT 'ÀD944516-98E6-44C5-849F-9C277833C01B'
UNION ALL
SELECT 'fish')
SELECT CASE
WHEN C LIKE expression + '%'
OR C LIKE '{' + expression + '}%' THEN CAST(C AS UNIQUEIDENTIFIER)
END
FROM   T
CROSS APPLY (SELECT REPLACE('00000000-0000-0000-0000-000000000000', '0', '[0-9a-fA-F]') COLLATE Latin1_General_BIN) C2(expression)
WHERE  C LIKE expression + '%'
OR C LIKE '{' + expression + '}%'
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A variant of r0d30b0y answer is to use PATINDEX to find within a string...

PATINDEX('%'+REPLACE('00000000-0000-0000-0000-000000000000', '0', '[0-9a-fA-F]')+'%',@StringToCompare) > 0

Had to use to find Guids within a URL string..

HTH

Dave

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I use :

ISNULL(convert(nvarchar(50), userID), 'NULL') = 'NULL'
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This is a function based on the concept of some earlier comments. This function is very fast.

CREATE FUNCTION [dbo].[IsGuid] (@input varchar(50))
RETURNS bit AS
BEGIN


RETURN
case when @input like '[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]-[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]-[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]-[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]-[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]'
then 1 else 0 end
END
GO


/*
Usage:


select [dbo].[IsGuid]('123') -- Returns 0
select [dbo].[IsGuid]('ebd8aebd-7ea3-439d-a7bc-e009dee0eae0') -- Returns 1


select * from SomeTable where dbo.IsGuid(TableField) = 0 -- Returns table with all non convertable items!


*/
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Like to keep it simple. A GUID has four - in it even, if is just a string

WHERE column like '%-%-%-%-%'

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I had some Test users that were generated with AutoFixture, which uses GUIDs by default for generated fields. My FirstName fields for the users that I need to delete are GUIDs or uniqueidentifiers. That's how I ended up here.

I was able to cobble together some of your answers into this.

SELECT UserId FROM [Membership].[UserInfo] Where TRY_CONVERT(uniqueidentifier, FirstName) is not null

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Though an older post, just a thought for a quick test ...

SELECT  [A].[INPUT],
CAST([A].[INPUT] AS [UNIQUEIDENTIFIER])
FROM   (
SELECT '5D944516-98E6-44C5-849F-9C277833C01B' Collate Latin1_General_100_BIN AS [INPUT]
UNION ALL
SELECT '{5D944516-98E6-44C5-849F-9C277833C01B}'
UNION ALL
SELECT '5D944516-98E6-44C5-849F-9C277833C01BXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
UNION ALL
SELECT '{5D944516-98E6-44C5-849F-9C277833C01B}ssssssssss'
UNION ALL
SELECT 'ÀD944516-98E6-44C5-849F-9C277833C01B'
UNION ALL
SELECT 'fish'
) [A]
WHERE   PATINDEX('[^0-9A-F-{}]%', [A].[INPUT]) = 0
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Use RLIKE for MYSQL

SELECT 1 WHERE @StringToCompare
RLIKE REPLACE('00000000-0000-0000-0000-000000000000', '0', '[0-9a-fA-F]');
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DECLARE @guid_string nvarchar(256) = 'ACE79678-61D1-46E6-93EC-893AD559CC78'


SELECT
CASE WHEN @guid_string LIKE '________-____-____-____-____________'
THEN CONVERT(uniqueidentifier, @guid_string)
ELSE NULL
END
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In a simplest scenario. When you sure that given string can`t contain 4 '-' signs.

SELECT * FROM City WHERE Name LIKE('%-%-%-%-%')
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In BigQuery you can use

SELECT *
FROM table
WHERE
REGEXP_CONTAINS(uuid, REPLACE('^00000000-0000-0000-0000-000000000000$', '0', '[0-9a-fA-F]'))

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