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Newsgroups: comp.databases.ms-sqlserver
Date: Mon, 25 Jul 2016 18:47:26 -0700 (PDT)
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Subject: to show full set of two tables
From: "M.G." <michael@gurfinkel.us>
Injection-Date: Tue, 26 Jul 2016 01:47:27 +0000
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Xref: csiph.com comp.databases.ms-sqlserver:1968

There is an assignment schedule where several entities are assigned on a daily basis, in ID/DATE simple fashion.

I need to report all IDS per every date in the work dates calendar, including instances where no assignment exists:

declare @ASSIGNMENTS	table
(	ID	int,
	XDATE	date 
);
					
declare @WORK_DATES	table
(	XDATE	date );

insert into @ASSIGNMENTS (ID, XDATE) values
(	100,	'20150506'),
(	100,	'20150507'),

(	222,	'20150505'),
(	222,	'20150506');

insert into @WORK_DATES (XDATE) values
(			'20150505'),
(			'20150506'),
(			'20150507'),
(			'20150508');

-- My solution is:
WITH FULL_SET (XDATE, ID) as 
(
	select DTS.XDATE
	,	IDS.ID
	from @WORK_DATES DTS
	cross apply (
		select distinct ID from @ASSIGNMENTS 
	) IDS
)
select 
	F.XDATE
,	A.ID
from FULL_SET F
left join @ASSIGNMENTS A on F.ID = A.ID and F.XDATE = A.XDATE
;

I am getting :

XDATE	ID
2015-05-05	NULL
2015-05-05	222
2015-05-06	100
2015-05-06	222
2015-05-07	100
2015-05-07	NULL
2015-05-08	NULL
2015-05-08	NULL

It works OK, but I suspect my solution could (and should) be simplified. Any ideas? 
Thanks in advance.