SELECT 
PS13.DCAP, 
PS13.AUSSL, 
PS13.C3, 
PS13.C4
FROM 
PS13
WHERE 
((PS13.DCAP Between #9/15/2014# And #9/15/2015#) AND (PS13.AUSSL="AUSSL 10")) 
UNION ALL 
SELECT DISTINCT 
IIf((DCount("*","Q1","((PS13.DCAP Between #9/15/2014# And #9/15/2015#) AND (PS13.AUSSL='AUSSL 10'))"))=0,0) AS DCAP, 
0 AS AUSSL, 
0 AS C3, 
0 AS C4
FROM 
PS13
WHERE 
((IIf((DCount("*","Q1","((PS13.DCAP Between #9/15/2014# And #9/15/2015#) AND (PS13.AUSSL='AUSSL 10'))"))=0,0)) Is Not Null)
;