SQL Server GUID sort algorithm. Why?

Question

Problem with UniqueIdentifiers

We have an existing database which uses uniqueidentifiers extensively (unfortunately!) both as primary keys and some

Answer 1

Here's a different approach. The GUID is simply shuffled around ready for a normal string comparison like it occurs in SQL Server. This is Javascript but it is very easy to convert to any language.

function guidForComparison(guid) {
  /*
  character positions:  
            11111111112222222222333333
  012345678901234567890123456789012345

  00000000-0000-0000-0000-000000000000

  byte positions:  
                          111111111111
  00112233 4455 6677 8899 001122334455
  */
  return guid.substr(24, 12) + 
         guid.substr(19, 4) + 
         guid.substr(16, 2) + 
         guid.substr(14, 2) + 
         guid.substr(11, 2) + 
         guid.substr(9, 2) + 
         guid.substr(6, 2) +
         guid.substr(4, 2) +
         guid.substr(2, 2) +
         guid.substr(0, 2);
};