Convert Procedural Approach into Set Based Approach in Sql-Server - sql

Question

We are using procedural approach (while loop) for inserting records into a particular table. the insert syntax is like below,
DECLARE #CNT INT = 0,
#WEEK DATE = '2015-11-01',
#FLAG INT
CREATE TABLE #Tmpdata (officeId int,id smallint, weekDate date,startsOn varchar(10),endsOn varchar(10),flag bit);
WHILE (#CNT <7)
BEGIN
SET #WEEK = DATEADD(D,#CNT,#WEEK )
IF EXISTS
(SELECT 1
FROM YEARRANGE
WHERE #WEEK BETWEEN CONVERT(DATE,taxseasonbegin)
AND CONVERT (DATE,taxSeasonEnd)
)
BEGIN
SET #FLAG =1
END
ELSE
BEGIN
SET #FLAG = 0
END
INSERT INTO #Tmpdata
(
officeId,id,weekDate,startsOn,endsOn,flag
)
VALUES
(
5134,#lvCounter,#week,'09:00 AM','05:00 PM',#flag
);
SET #cnt=#cnt+1;
end
(NOTE : TaxSeason is from january to august).
Is it possible to re-write the above logic in set based approach?

Answer 1

This is making a number of assumption because you didn't post ddl or any consumable sample data. Also, there is a variable #lvCounter not defined in your code. This is perfect opportunity to use a tally or numbers table instead of a loop.
declare #lvCounter int = 42;
DECLARE #CNT INT = 0,
#WEEK DATE = '2015-11-01',
#FLAG INT;
WITH
E1(N) AS (select 1 from (values (1),(1),(1),(1),(1),(1),(1),(1),(1),(1))dt(n))
, cteTally(N) AS
(
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E1
)
select 5134 as officeId
, #lvCounter as Id
, DATEADD(DAY, N - 1, #WEEK) as weekDate
, '09:00 AM' as startsOn
, '05:00 PM' as EndOn
, Flag
from cteTally t
cross apply
(
select CAST(count(*) as bit) as Flag
from YearRange
where DATEADD(Day, t.N, #WEEK) > CONVERT(DATE,taxseasonbegin)
AND DATEADD(Day, t.N, #WEEK) <= CONVERT (DATE,taxSeasonEnd)
) y
where t.N <= 7;

Answer 2

Please can you provide sample data?
You can do something like:
SELECT DateIncrement = SUM(DATEADD(D,#CNT,#WEEK)) OVER (ORDER BY officeID)
FROM...
This gets an incremented date value for each record which you can then check against your start and end dates.

Answer 3

You could try some Kind of this one. This gives you the data I think you Need for your insert. I do not have a table named YEARRANGE so I couldn't test it completely
DECLARE #CNT INT = 0, #WEEK DATE = '2015-11-01', #FLAG INT;
CREATE TABLE #Tmpdata (officeId int,id smallint, weekDate date,startsOn varchar(10),endsOn varchar(10),flag bit);
WITH CTE AS
(
SELECT num AS cnt,
DATEADD(D, SUM(num) OVER(ORDER BY num ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)
, #WEEK) AS [week]
FROM
(
SELECT ROW_NUMBER() OVER (ORDER BY nl) -1 AS num
FROM
(SELECT NULL AS nl UNION ALL SELECT NULL AS nl UNION ALL SELECT NULL AS nl UNION ALL SELECT NULL AS nl
UNION ALL SELECT NULL AS nl UNION ALL SELECT NULL AS nl UNION ALL SELECT NULL AS nl
) AS ni
) AS no
)
INSERT INTO #Tmpdata (officeId,id,weekDate,startsOn,endsOn,flag)
SELECT 5134 AS officeID, cnt AS id, [week],'09:00 AM' AS startsOn,'05:00 PM' AS endsOn, COALESCE(A1.flag,0) AS flag
FROM CTE
OUTER APPLY (SELECT 1
FROM YEARRANGE
WHERE [week] BETWEEN CONVERT(DATE,taxseasonbegin)
AND CONVERT (DATE,taxSeasonEnd)
) AS A1(flag);