The NEWID() function returns a uniqueidentifier for each row of data that is returned.

Execute the following query in the AdventureWorks database:

select top 5 productid, name from production.productorder by newid()

Here are the results:

productid   name----------- --------------------------------------------------917         LL Mountain Frame - Silver, 42722         LL Road Frame - Black, 58372         Thin-Jam Hex Nut 8969         Touring-1000 Blue, 60328         Mountain End Caps(5 row(s) affected)

Execute the query again and you get a completely different set of results:

productid   name----------- --------------------------------------------------861         Full-Finger Gloves, S440         Lock Nut 16526         HL Shell451         Lock Nut 11406         External Lock Washer 5(5 row(s) affected)