Note: fix those SIDS

Big fat disclause: Microsoft does not
Support any modifications to your SharePoint databases. That's not
Say they won't support your SharePoint site, but if this operation
Breaks your server, Microsoft won't help you. I'm not responsible
The results, either, while we're on the subject of passing the buck.
Back up your database.

Okay, now that we 've gotten that mumbo-jumbo out of the way, here's the code.

 Declare @ Login Varchar (40), @ systemid Varbinary (128)

 Declare Curusers Cursor   Local   For  
Select Tp_login, tp_systemid From Userinfo Where Tp_deleted = 0

 Open Curusers

 Fetch   Next   From Curusers Into @ Login, @ systemid

 While   @ Fetch_status = 0
 Begin 
 Print   'Resetting user' + @ Login +'To New Sid' 
 Print Suser_sid (@ login)
 Update Userinfo
 Set Tp_systemid = suser_sid (tp_login) Where   Current   Of Curusers
 Fetch   Next   From Curusers Into @ Login, @ systemid
 End 

 Close Curusers
Deallocate Curusers

Go