Progressive sql update statement

Question

6I have two table as follows, TABLEA:

MEMBER_ID   CLIENT_ID   TENTATIVE_ID    TENTATIVE_START_DATE
1   65239   26  6/15/2012
2   63693   NULL    NULL
3   5549    NULL    NULL
4   85452   NULL    NULL
5   77898   11  6/15/2012
6   93119   21  6/15/2012
7   7876    26  6/20/2012
8   27572   26  6/21/2012
9   15524   26  6/21/2012
10  39465   8   6/21/2012
11  10143   26  6/23/2012
12  72828   NULL    NULL

TABLE B:

TENTATIVE_ID    LAST_AUTO_ASSIGNED_ON
26  6/15/2012
11  6/16/2012
21  6/13/2012
27  6/20/2012
28  6/22/2012
29  6/25/2012
8   6/26/2012
21  6/24/2012

Situation is that I need to update the nulls in table A with TENTATIVE_IDs from table B based on minimum LAST_AUTO_ASSIGNED_ON value and every time an id is assigned LAST_AUTO_ASSIGNED_ON is updated with current date time for that id in table B.

In this way we loop though all the tentative ids in table B and assign them to table A.

I am not allowed to use cursor. How could I achieve this?

Thanks!

Answer 1

Update Tablea set tablea.tentative_id = (select top 1 tableb.tentative_id from tableb order by Last_auto_assigned_on, tentative_id), Tentative_start_date = getdate() from tablea where tablea.tentative_id is null

Update tableb set last_auto_assigned_on = getdate() where tentative_id = (select top 1 tableb.tentative_id from tableb order by Last_auto_assigned_on, tentative_id)