I am not sure which is correct, your explanation or your desired output. The stated rules, the sample data and the output you said you wanted don't match up.

In your output you have App1 as NULL but your rule says it should be "True".

App2 has 2 rows for AIX but the Adder values are the same. According to the rules shouldn't this also be "True".

I cobbled together something resembling ddl and sample data in a format you should post with in the future.

create table #SomeTable

(

AppName char(4),

OS varchar(10),

Adder char(3)

)

insert #SomeTable

select 'App1', 'Windows', Null union all

select 'App1', 'Linux', 'UDB' union all

select 'App1', 'AIX ', 'UDB' union all

select 'App1', 'Linux', 'Sql' union all

select 'App2', 'AIX', 'UDB' union all

select 'App2', 'Windows', 'UDB' union all

select 'App2', 'Linux', 'UDB' union all

select 'App2', 'AIX', 'UDB'

Now to setup some data that meets the requirements of rule #2 I added some more data.

insert #SomeTable

select 'App3', 'AIX', 'UDB' union all

select 'App3', 'Windows', 'UDB' union all

select 'App3', 'Linux', 'UDB' union all

select 'App3', 'AIX', 'xxx'

OK. Now we have something to work with. If I understand your requirements I think you want something along these lines.

select *, case MyCount when 1 then 'True' end

from #SomeTable s

cross apply (select COUNT(distinct Adder) as MyCount from #SomeTable s2 where s2.AppName = s.AppName and s2.OS = 'AIX') x