sql server - What is the most efficient way to generate 8 character random alphanumeric string in TSQL?

Question

I want to generate a unique 8 character random alphanumeric string in TSQL, for a mail confirm link. We are currently using a GUID but it is not very user friendly.

It only really has to obey a few rules:

• be 8 Characters long
• be unique
• be generated efficiently

Answer 1

SUBSTRING(CONVERT(varchar(255), NEWID()), 0, 7)