Question

I imagine this has been done many time before but I can’t for the life of me figure it out and I am tired of trying work arounds.

I have two tables.
One is an Object having ObjectID(key), Name, Type, Location
Two is ObjectStatus having StatusID(key),ObjectID,Status,DateChanged,UserWhoChangedStatus

What I want to do is return all Objects and the ObjectStatus that was entered last

Table 1 Object

ObjectID      Name          Type      Location
   1         Blue Ball      Ball       ToyBox
   2         Red Ball       Ball       ToyBox

Table 2 (ObjectStatus)

StatusID    ObjectID    Status    DateChanged    UserWhoChangedStatus
   1          2         Broken    2012-01-25       56481
   2          2         Fixed     2012-01-30       98526
   3          1         Bouncy    2012-01-05       85245
   4          1         Sticky    2012-02-10       56481

I would want to get returned

ObjectID Name      Type Location StatusID Status DateChanged UserWhoChangedStatus
   1     Blue Ball Ball ToyBox       4    Sticky 2012-02-10  56481
   2     RedBall   Ball ToyBox       2    Fixed  2012-01-30  98526

Which is all Objects and the ObjectStatus that was last entered

Answer 1

Since you didn’t say the DBMS I will assume Ms Sql Server.

SELECT
   O.*,
   S.*
FROM
   dbo.Object O
   OUTER APPLY (
      SELECT TOP 1 *
      FROM dbo.ObjectStatus S
      WHERE O.ObjectID = S.ObjectID
      ORDER BY DateChanged DESC
   ) S