How do I combine 2 select statements into one?

Question

I am a noob when it comes to SQL syntax.

I have a table with lots of rows and columns of course :P Lets say it looks like this:

      AAA BBB CCC DD         


        

Answer 1

Thanks for the input. Tried the stuff that has been mentioned here and these are the 2 I got to work:

(
select 'OK', * from WorkItems t1
where exists(select 1 from workitems t2 where t1.TextField01=t2.TextField01 AND (BoolField05=1) )
AND TimeStamp=(select max(t2.TimeStamp) from workitems t2 where t2.TextField01=t1.TextField01) 
AND TimeStamp>'2009-02-12 18:00:00'
AND (BoolField05=1)
)
UNION
(
select 'DEL', * from WorkItems t1
where exists(select 1 from workitems t2 where t1.TextField01=t2.TextField01 AND (BoolField05=1) )
AND TimeStamp=(select max(t2.TimeStamp) from workitems t2 where t2.TextField01=t1.TextField01) 
AND TimeStamp>'2009-02-12 18:00:00'
AND NOT (BoolField05=1)
)

AND

select 
    case
        when
            (BoolField05=1)
    then 'OK'
    else 'DEL'
        end,
        *
from WorkItems t1
Where
            exists(select 1 from workitems t2 where t1.TextField01=t2.TextField01 AND (BoolField05=1) )
            AND TimeStamp=(select max(t2.TimeStamp) from workitems t2 where t2.TextField01=t1.TextField01) 
            AND TimeStamp>'2009-02-12 18:00:00'

Which would be the most efficient of these (edit: the second as it only scans the table once), and is it possible to make it even more efficient? (The BoolField=1) is really a variable (dyn sql) that can contain any where statement on the table.

I am running on MS SQL 2005. Tried Quassnoi examples but did not work as expected.