Question

I have two tables with data
tab1.

------------------------------------------------------------
compid    |  user_id   |    compdate    |     description   |
------------------------------------------------------------
C0001     |  U000001   |   2012-02-29   |      desc1        |
C0002     |  U000002   |   2012-02-29   |      desc1        |
C0003     |  U000001   |   2012-03-01   |      desc1        |
C0004     |  U000003   |   2012-03-01   |      desc1        |
C0005     |  U000001   |   2012-03-02   |      desc1        |
C0006     |  U000008   |   2012-03-02   |      desc1        |
C0007     |  U000212   |   2012-03-02   |      desc1        |
C0008     |  U010222   |   2012-03-02   |      desc1        |
C0009     |  U000091   |   2012-03-02   |      desc1        |
C0010     |  U010222   |   2012-03-02   |      desc1        |
------------------------------------------------------------

tab2.

------------------------------------------------------------
compid    | assigned_to|    assignedon  |     status        |
------------------------------------------------------------
C0001     |  U000101   |   2012-02-29   |      Closed        |
C0002     |  U000101   |   2012-02-29   |      Open          |
C0003     |  U000102   |   2012-03-02   |      Closed        |
C0004     |  U000102   |   2012-03-02   |      Closed        |
C0005     |  U000101   |   2012-03-02   |      Open          |
C0006     |  U000101   |   2012-03-02   |      Closed        |
C0008     |  U000101   |   2012-03-02   |      Closed        |
------------------------------------------------------------

Now what I want is:
All the records whose Status = 'Open' and also the record from tab1 whose entry is not in tab2.
The query should fetch records whose compdate = '2012-03-02'.

What I tried is:

select  
 from tab1 a 
      left join dbo.tab2 b 
      on a.CompId = b.CompId 
where b.StatusFlag = 'Open' 
  and a.CompDate = CONVERT(nvarchar(30),Dateadd(day,-1,getdate()),106) 

Expected results :

---------------------------------------------------------------------------------------
 compid  |  user_id   |    compdate    |description  |assigned_to  | assignedon |status| 
---------------------------------------------------------------------------------------
 C0005   |  U000001   |   2012-03-02   |   desc1     | U000101     | 2012-03-02 | open |   
 C0009   |  U000001   |   2012-03-02   |   desc1     | Null        | NULL       | null |
 C0010   |  U000001   |   2012-03-02   |   desc1     | null        | null       | null |
----------------------------------------------------------------------------------------

Answer 1

Select *
From 
   Tab1
Left Join
   Tab2
on 
   Tab1.CompID = Tab2.CompID
Where
   (Tab2.Status = 'open' or 
   Tab2.Status is null) and
   Tab1.CompDate = '2012-03-02'