Convert HashBytes to VarChar

Question

I want to get the MD5 Hash of a string value in SQL Server 2005. I do this with the following command:

SELECT HashBytes(\'MD5\', \'HelloWorld\')

Answer 1

I have found the solution else where:

SELECT SUBSTRING(master.dbo.fn_varbintohexstr(HashBytes('MD5', 'HelloWorld')), 3, 32)

Answer 2

SELECT CONVERT(NVARCHAR(32),HashBytes('MD5', 'Hello World'),2)

Answer 3

With personal experience of using the following code within a Stored Procedure which Hashed a SP Variable I can confirm, although undocumented, this combination works 100% as per my example:

@var=SUBSTRING(master.dbo.fn_varbintohexstr(HashBytes('SHA2_512', @SPvar)), 3, 128)

Answer 4

Changing the datatype to varbinary seems to work the best for me.

Answer 5

Use master.dbo.fn_varbintohexsubstring(0, HashBytes('SHA1', @input), 1, 0) instead of master.dbo.fn_varbintohexstr and then substringing the result.

In fact fn_varbintohexstr calls fn_varbintohexsubstring internally. The first argument of fn_varbintohexsubstring tells it to add 0xF as the prefix or not. fn_varbintohexstr calls fn_varbintohexsubstring with 1 as the first argument internaly.

Because you don't need 0xF, call fn_varbintohexsubstring directly.

Answer 6

Contrary to what David Knight says, these two alternatives return the same response in MS SQL 2008:

SELECT CONVERT(VARCHAR(32),HashBytes('MD5', 'Hello World'),2)
SELECT UPPER(master.dbo.fn_varbintohexsubstring(0, HashBytes('MD5', 'Hello World'), 1, 0))

So it looks like the first one is a better choice, starting from version 2008.