How to set identity seed value using variable in SQL Server

Question

I have a table with columns id, items :

 ID    Items
----------------
 1      mc3
 2      mc2
 3      mc1

I want to insert this data into a temp table but the order of items in descending ie

 ID     Items
--------------
  1     mc1
  2     mc2
  3     mc3

but I can't take order by of these items. items column has duplicate values. I tried to use identity column but that was a terrible idea. I will show that query.

  DECLARE @totalNO INT = 0

  SET @totalNO = (SELECT COUNT(*) FROM @tblmc)

  SELECT IDENTITY(INT, @totalNO, -1) RowIndex1, * 
  INTO #tempmcfordesc 
  FROM @tblmc.

but this query causes an error. Is there any other way? I can loop the table and insert but I just want to know is there any easy way for this. Please sort this out.

Answer 1

if you have create the temp table then use this :

INSERT INTO #temptable
SELECT Row_Number()
         OVER (
           ORDER BY ID DESC) AS ID,
       Items
FROM   yourtable

and if you haven't created the temp table then create it with data like this :

SELECT Row_Number()
         OVER (
           ORDER BY ID DESC) AS ID,
       Items
INTO   #temptable
FROM   yourtable