T-SQL - Filtered dates between a range

Question

Code:

DECLARE @T1 TABLE ([ID] INT, [WD] DATE, [SD] DATETIME, [ED] DATETIME, [Val] INT)
INSERT INTO @T1 ( [ID], [WD], [SD], [ED], [VAL] )
VALUES  ( 1, '2016-02-14', '2016-02-14 08:00:00', '2016-02-14 16:30:00', 12 )
        ,( 1, '2016-02-14', '2016-02-16 08:00:00', '2016-02-16 16:30:00', 15 )
        ,( 3, '2016-02-14', '2016-02-16 08:00:00', '2016-02-16 16:30:00', 12 )
        ,( 1, '2016-02-21', '2016-02-22 08:00:00', '2016-02-22 16:30:00', 100 )
        ,( 2, '2016-02-21', '2016-02-25 08:00:00', '2016-02-25 16:30:00', 124 )
        ,( 3, '2016-03-20', '2016-03-21 08:00:00', '2016-03-21 16:30:00', 10 )
        ,( 3, '2016-04-17', '2016-04-17 08:00:00', '2016-04-17 16:30:00', 8 );

DECLARE @StartDate DATE
        , @EndDate DATE;

SELECT @StartDate = MIN(WD) FROM @T1
SELECT @EndDate = DATEADD(DAY,6,MAX(WD)) FROM @T1;

DECLARE @T2 TABLE (D DATE) -- Table generated to get ALL dates between the minium WD (Min Sunday) and 6 days after the maximum WD (Max Sunday + 6 days to complete the week date range)
INSERT INTO @T2 ( [D] )
SELECT  DATEADD(DAY, NBR - 1, @StartDate)
FROM    ( SELECT ROW_NUMBER() OVER ( ORDER BY c.object_id ) AS NBR
          FROM   sys.columns c
        ) NBR
WHERE   NBR - 1 <= DATEDIFF(DAY, @StartDate, @EndDate);

SELECT * FROM @T1;
SELECT * FROM @T2;

Description: @T1 is the pre-populated source data table with specific dates where [ID] = an ID field of some sort, [WD] = Different start of the week (Sundays), [SD] = Start of a day within that [WD] week, [ED] = End of a day within that [WD] week, [Val] = Some assigned value for that ID/WD/SD/ED record

@T2 is the table I'm defining and populating to get all the dates within MIN([WD]) and MAX([WD]) + 6 days (to compelte the week)

Goal:

Return @T1 data along with any missing dates for those [ID]/[WD] weeks. (refer to Desired Output for better understanding)

Desired result (copied from Excel so the format is different, but that's ok)

[ID][WD]        [SD]            [ED]            [Val]
1   2/14/2016   2/14/16 8:00    2/14/16 16:30   12
1   2/14/2016   2/15/16 00:00   2/15/16 00:00   NULL
1   2/14/2016   2/16/16 8:00    2/16/16 16:30   15
1   2/14/2016   2/17/16 00:00   2/17/16 00:00   NULL
1   2/14/2016   2/18/16 00:00   2/18/16 00:00   NULL
1   2/14/2016   2/19/16 00:00   2/19/16 00:00   NULL
1   2/14/2016   2/20/16 00:00   2/20/16 00:00   NULL
3   2/14/2016   2/14/16 00:00   2/14/16 00:00   NULL
3   2/14/2016   2/15/16 00:00   2/15/16 00:00   NULL
3   2/14/2016   2/16/16 8:00    2/16/16 16:30   12
3   2/14/2016   2/17/16 00:00   2/17/16 00:00   NULL
3   2/14/2016   2/18/16 00:00   2/18/16 00:00   NULL
3   2/14/2016   2/19/16 00:00   2/19/16 00:00   NULL
3   2/14/2016   2/20/16 00:00   2/20/16 00:00   NULL
1   2/21/2016   2/21/16 00:00   2/21/16 00:00   NULL
1   2/21/2016   2/22/16 8:00    2/22/16 16:30   100
1   2/21/2016   2/23/16 00:00   2/23/16 00:00   NULL
1   2/21/2016   2/24/16 00:00   2/24/16 00:00   NULL
1   2/21/2016   2/25/16 00:00   2/25/16 00:00   NULL
1   2/21/2016   2/26/16 00:00   2/26/16 00:00   NULL
1   2/21/2016   2/27/16 00:00   2/27/16 00:00   NULL
2   2/21/2016   2/21/16 00:00   2/21/16 00:00   NULL
2   2/21/2016   2/22/16 00:00   2/22/16 00:00   NULL
2   2/21/2016   2/23/16 00:00   2/23/16 00:00   NULL
2   2/21/2016   2/24/16 00:00   2/24/16 00:00   NULL
2   2/21/2016   2/25/16 8:00    2/25/16 16:30   124
2   2/21/2016   2/26/16 00:00   2/26/16 00:00   NULL
2   2/21/2016   2/27/16 00:00   2/27/16 00:00   NULL
3   3/20/2016   3/20/16 00:00   3/20/16 00:00   NULL
3   3/20/2016   3/21/16 8:00    3/21/16 16:30   10
3   3/20/2016   3/22/16 00:00   3/22/16 00:00   NULL
3   3/20/2016   3/23/16 00:00   3/23/16 00:00   NULL
3   3/20/2016   3/24/16 00:00   3/24/16 00:00   NULL
3   3/20/2016   3/25/16 00:00   3/25/16 00:00   NULL
3   3/20/2016   3/26/16 00:00   3/26/16 00:00   NULL
3   4/17/2016   4/17/16 8:00    4/17/16 16:30   8
3   4/17/2016   4/18/16 00:00   4/18/16 00:00   NULL
3   4/17/2016   4/19/16 00:00   4/19/16 00:00   NULL
3   4/17/2016   4/20/16 00:00   4/20/16 00:00   NULL
3   4/17/2016   4/21/16 00:00   4/21/16 00:00   NULL
3   4/17/2016   4/22/16 00:00   4/22/16 00:00   NULL
3   4/17/2016   4/23/16 00:00   4/23/16 00:00   NULL

I tried using cross join and stuff but no luck with getting the desired output.

Answer 1

I removed your @T2 and use my @T3 instead.

DECLARE @T1 TABLE ([ID] INT, [WD] DATE, [SD] DATETIME, [ED] DATETIME, [Val] INT)
INSERT INTO @T1 ( [ID], [WD], [SD], [ED], [VAL] )
VALUES  ( 1, '2016-02-14', '2016-02-14 08:00:00', '2016-02-14 16:30:00', 12 )
        ,( 1, '2016-02-14', '2016-02-16 08:00:00', '2016-02-16 16:30:00', 15 )
        ,( 3, '2016-02-14', '2016-02-16 08:00:00', '2016-02-16 16:30:00', 12 )
        ,( 1, '2016-02-21', '2016-02-22 08:00:00', '2016-02-22 16:30:00', 100 )
        ,( 2, '2016-02-21', '2016-02-25 08:00:00', '2016-02-25 16:30:00', 124 )
        ,( 3, '2016-03-20', '2016-03-21 08:00:00', '2016-03-21 16:30:00', 10 )
        ,( 3, '2016-04-17', '2016-04-17 08:00:00', '2016-04-17 16:30:00', 8 );

DECLARE @T3 TABLE ([ID] INT, [WD] DATE, [SD] DATETIME, [ED] DATETIME);
WITH cte AS (
SELECT DISTINCT ID, WD
FROM
    @T1
)
INSERT INTO @T3 (ID, WD, SD, ED)
SELECT ID, WD, DATEADD(DAY,n,WD), DATEADD(DAY,n,WD)
FROM
    cte
    CROSS JOIN (VALUES (0),(1),(2),(3),(4),(5),(6)) AS ADDED(n);

SELECT t3.ID, t3.WD,COALESCE(t1.SD,t3.SD) AS SD, COALESCE(t1.ED,t3.ED) AS ED, t1.Val
FROM @T3 t3
    LEFT JOIN @T1 t1 ON t3.ID=t1.ID AND CONVERT(DATE,t1.SD)=CONVERT(DATE,t3.SD)

Answer 2

This would be a left join of your source data against the timeline you created.

I could not figure out how the ID is assigned, but when I use COALESCE to fill up missing values this returns your desired output (except ID):

SELECT  [t1].[ID]
       ,COALESCE([t1].[WD], DATEADD(DAY, 1 - DATEPART(WEEKDAY, [t2].[D]), [t2].[D])) AS WD
       ,COALESCE([t1].[SD], [t2].[D]) AS SD
       ,COALESCE([t1].[ED], [t2].[D]) AS ED
       ,[t1].[Val]
FROM    @T2 [t2]
LEFT JOIN @T1 [t1]
ON      [t2].[D] = CONVERT(DATE, [t1].[SD]);