Method 1: Using a cursor

declare cursor1 cursor local for select * from tablename
open cursor1
fetch next from cursor1 into #temptable
while @@fetch_status = 0
begin
if exists (select column from tablename where 
        id = (select id from #temptable))
    begin 
        /* do stuff here */ 
    end
else
    begin
        /* do other stuff here */
    end 
if object_id('tempdb..#temptable') is not null
        drop table #temptable
fetch next from cursor1 into #temptable
end
close cursor1
deallocate cursor1

Method 2: Using a temporary table with primary key         (via: http://support.microsoft.com/kb/111401)

declare @au_id char( 11 )
set rowcount 0
select * into #mytemp from authors
set rowcount 1
select @au_id = au_id from #mytemp
while @@rowcount <> 0
begin
    set rowcount 0
    select * from #mytemp where au_id = @au_id
    delete #mytemp where au_id = @au_id
    set rowcount 1
    select @au_id = au_id from #mytemp<BR/>
end
set rowcount 0

Method 3: Using a temporary table without primary key         (via: http://support.microsoft.com/kb/111401)

set rowcount 0
select NULL mykey, * into #mytemp from authors
set rowcount 1
update #mytemp set mykey = 1
while @@rowcount > 0
begin
    set rowcount 0
    select * from #mytemp where mykey = 1
    delete #mytemp where mykey = 1
    set rowcount 1
    update #mytemp set mykey = 1
end
set rowcount 0