Hi,

> does this code will not return duplicate? just like sys(2015) w/c is base on time? I want to put it on a unique field.

Yes, it does return duplicate values. If you need a unique value, you can use NEWID(). This value is virtually guaranteed to be unique. However, it's more than 10 characters long (36 precisely). You can reduce it to 32 characters if you remove the "-", or 16 bytes if you use a uniqueidentifier field type which stores the same value in binary format.