declare @T TABLE (id int identity(1,1),[Name] nvarchar(20), Randnum int)

insert @T ([Name])

select 'A1' union all

select 'A2' union all

select 'A3' union all

select 'A4' union all

select 'A5' union all

select 'A6' union all

select 'A7' union all

select 'A8' union all

select 'A9' union all

select 'A10' union all

select 'A11' union all

select 'A12'

select * from @T

/*

id          Name                 Randnum

----------- -------------------- -----------

1           A1                   NULL

2           A2                   NULL

3           A3                   NULL

4           A4                   NULL

5           A5                   NULL

6           A6                   NULL

7           A7                   NULL

8           A8                   NULL

9           A9                   NULL

10          A10                  NULL

11          A11                  NULL

*/

update @T

set Randnum=rand()*1000

select * from @T

/*

id          Name                 Randnum

----------- -------------------- -----------

1           A1                   357

2           A2                   357

3           A3                   357

4           A4                   357

5           A5                   357

6           A6                   357

7           A7                   357

8           A8                   357

9           A9                   357

10          A10                  357

11          A11                  357

12          A12                  357

*/

update @T

set Randnum=(select cast(ceiling(rand(checksum(newid()))*100) as  int))

select * from @T

/*

id          Name                 Randnum

----------- -------------------- -----------

1           A1                   28

2           A2                   52

3           A3                   66

4           A4                   3

5           A5                   97

6           A6                   100

7           A7                   61

8           A8                   65

9           A9                   82

10          A10                  62

11          A11                  68

12          A12                  7

*/