First instance 0 rest other become 1 in SQL Server

Question

I have a scenario where IF ID, Code and InsertDate is same and if it is 1st entry then it will be 0 else 1.

Demo data:

CREATE TABLE #test 
(
     ID int,
     code int,
     InsertDate datetime2
)

Insert into #test values (1,1,'2019-09-17 03:19:00.0000000')
Insert into #test values (1,1,'2019-09-17 03:19:00.0000000')
Insert into #test values (1,1,'2019-09-17 03:19:00.0000000')
Insert into #test values (2,1,'2019-09-17 03:19:00.0000000')
Insert into #test values (3,1,'2019-09-17 03:19:00.0000000')

Expected o/p

ID  code    InsertDate              flag   
-----------------------------------------
1    1  2019-09-17 03:19:00.0000000  0     
1    1  2019-09-17 03:19:00.0000000  1     
1    1  2019-09-17 03:19:00.0000000  1     
2    1  2019-09-17 03:19:00.0000000  0     
3    1  2019-09-17 03:19:00.0000000  0     

What I tried

SELECT
    *,
    ROW_NUMBER() OVER (PARTITION BY ID, Code, Insertdate ORDER BY InsertDate) flag 
FROM #test

With this I got the initial logic but what to do next I need help.

Answer 1

A simple CASE expression may help:

SELECT
   *,
   CASE 
      WHEN ROW_NUMBER() OVER (PARTITION BY ID, Code, Insertdate ORDER BY InsertDate) = 1 THEN 0 
      ELSE 1 
   END AS Flag
FROM #test