CTE recursive select and insert in same table with new id's and some updated fields

Question

Let's say I have this table:

|TeamId |Name           |ActiveYear |ParentTeamId |OriginTeamId |
+-------+---------------+-----------+-------------+-------------+
|1      |Founding Team  |2020       |NULL         |NULL         |
|2      |Elders Team    |2020       |1            |NULL         |
|3      |Younger Team   |2020       |1            |NULL         |
|4      |Women Team     |2020       |2            |NULL         |
|5      |Men´s Team     |2020       |2            |NULL         |

When I query it, I can see the hierarchy:

WITH abcd AS 
(
    -- anchor
    SELECT 
        CAST((Convert(varchar(20), TeamId)) AS VARCHAR(1000)) AS "Tree",
        TeamId, [Name], Activeyear, ParentTeamId, OriginTeamId
    FROM    
        Teams AS p
    WHERE   
        ParentTeamId IS NULL And ActiveYear = 2020

    UNION ALL

    --recursive member
    SELECT  
        CAST((CONVERT(varchar(20), a.tree) + '/' + CONVERT(varchar(20), c.TeamId)) AS VARCHAR(1000)) AS "Tree",
        c.TeamId, c.[Name], c.Activeyear, c.ParentTeamId, c.OriginTeamId
    FROM
        Teams AS c
    JOIN 
        abcd AS a ON c.ParentTeamId = a.TeamId
    WHERE   
        c.ActiveYear = 2020
) 
SELECT * 
FROM abcd

Now, I need to update this table, recreating the same structure but with new id's and the Activeyear = 2021.

So, the new parent record will still be the parent of the other new records.

I want to make a query, which permit me to "clone" this data and insert it with some updates: ActiveYear = 2021, OriginTeamId(OriginTeamId is to identify where that info came from)

How can I do that?

Answer 1

One way to do this is in two steps. Insert the rows without the ids. Then figure out the ids:

insert into teams (name, activeyear, parentid)
    select name, 2021, parentid
    from teams
    where actdiveyear = 2020;

Now update the values by looking up the corresponding ids. Window functions can help here:

insert into teams (name, activeyear, ParentTeamId)
    select name, 2021, ParentTeamId
    from teams
    where activeyear = 2020;

with corresponding as (
      select t2020.teamid  as teamid_2020, t2021.teamid as teamid_2021
      from teams t2020 join
           teams t2021
           on t2020.name = t2021.name
      where t2020.activeyear = 2020 and t2021.activeyear = 2021
     )
update t
    set ParentTeamId = c.teamid_2021
    from teams t join
         corresponding c
         on t.ParentTeamId = c.teamid_2020
     where t.activeyear = 2021;

Here is a db<>fiddle.