Join query on access

Try this:

Select * from [table a] as A
    left outer join [table b] as B on A.asid = B.asid
where a.check1 = 1
  and a.check2 = 1
  and a.check3 is not null
  and (b.asid is null or b.smth = 1)

try this:

select a.*, b.asisid as b_asisid from (
select * from a left join b on a.asisid= b.asisid
) x where ((b_asisid is null) or (b_asisid is not null and b.smth=1))
and A.check1 = 1 and
and A.check2 = 1 and
and A.check3 is not null

@shaun kline

I used your query and it seems almost perfect.
I have two problems which probably occur due to me giving wrong specification

The relation A-B is one to many.
A) If at least one b.smth for one record of A is 0 then i do not want that A record in the results set

B) If one record of A has two instances on B with b.smth = 1 then i need only one appearance of A in the results set

Could you help me futhermore please?

try this( this query will not produce duplicate a record):

Select * from [table a] as a
where a.check1 = 1
  and a.check2 = 1
  and a.check3 is not null
  and a.asid not in (select asid from B group by asid having sum(iif(b_smth=0,1,0))>0)

@HainKurt

I do not understand the syntax iif(b_smth=0,1,0))>0)

B.smth actually takes the value "trial" and "regular" not 0 and 1
Could you syntax it for me once again because every effort of mine produced a syntax error??
Will this query produce exactly what i needed???

If you only want the record from table a without any data from table b, try this:

select *
from [table a]
where check1 = 1
  and check2 = 1
  and check3 is not null
  and asid not in (select asid from [table b] where smth = 0)

If you want values from one record in table b, you will need to let us know what field (including data type) will make the distinction and whether it should be the first (min) or last (max).