Generate serial numbers

I simply needed to generate serial numbers. I tried out so many options to generate it. But only with the help any other table I could achieve it.

Supposing Table1 has 10 records, below script can generate serial numbers from 1 to 10. if you want more numbers you need to select the table having sufficient records as per your requirement.

SELECT ROW_NUMBER() OVER (ORDER BY Nums) AS slno FROM Table1

If you want to generate serial numbers till 1 to 5 then you can use

SELECT TOP 5 ROW_NUMBER() OVER (ORDER BY Nums) AS slno FROM Table1

Table1

uniqid	Nums
NULL	data1
NULL	data2
NULL	data3
NULL	data4
NULL	data5
NULL	data6
NULL	data7
NULL	data8
NULL	data9
NULL	data10

Update Serial number to an existing column.
 Assume table1 has a NULL column by name uniqid. I need to update serial numbers starting from 1. So here is the query to achieve this.

WITH cte as
(
SELECT uniqid,
ROW_NUMBER() OVER(ORDER BY (SELECT 0)) as rnk
FROM table1
)
UPDATE cte SET uniqid=rnk

If we need to update serial numbers starting from 101 then the query is

WITH cte as
(
SELECT uniqid,
ROW_NUMBER() OVER(ORDER BY (SELECT 0)) as rnk
FROM table1
)
UPDATE cte SET uniqid=100+rnk