How to insert values based on another column value - sql

Question

Below is a subset of my table (for the first id)
date
id
value
01/01/2022
1
5
08/01/2022
1
2
For each id, the dates are not consecutive (e.g., for id 1, the min date is 01/01/2022 and the max date is 08/01/2022)--there are 7 days in between both dates. I want to insert rows to make the dates for each id consecutive and contiguous - the value for the value field/column to be filled with 0s so that the updated table looks like:
date
id
value
01/01/2022
1
5
02/01/2022
1
0
03/01/2022
1
0
04/01/2022
1
0
05/01/2022
1
0
06/01/2022
1
0
07/01/2022
1
0
08/01/2022
1
2
Any SQL code on how to implement this would be highly appreciated. I have a calendar table but am unsure how to join it with the above table so that I fill in missing dates dynamically for each id with 0s.
My calendar table looks like:
date
01/01/2022
02/01/2022
03/01/2022
04/01/2022

Answer 1

Considering you state you have a calendar table, it seems what you need to do with JOIN to it with the MIN and MAX dates from your other table, and the LEFT JOIN back to your table:
WITH MinMax AS(
SELECT ID,
MIN(date) AS MinDate,
MAX(date) AS MaxDate
FROM dbo.YourTable
GROUP BY ID),
Dates AS(
SELECT MM.ID,
C.CalendarDate AS [Date]
FROM MinMax MM
JOIN dbo.CalendarTable C ON MM.MinDate <= C.CalendarDate
AND MM.MaxDate >= C.CalendarDate)
SELECT D.ID,
D.[Date],
ISNULL(YT.[Value],0) AS [Value]
FROM Dates D
LEFT JOIN dbo.YourTable YT ON D.ID = YT.ID
AND D.[Date] = YT.[Date];

Answer 2

SET DATEFORMAT DMY
-- CREATE A TABLE WITH OUR INPUT DATA
DROP TABLE IF EXISTS #TheData
GO
CREATE TABLE #TheData
(TheDate DATE, id INT, TheValue INT)
INSERT INTO #TheData
(TheDate,id,Thevalue)
VALUES
('01/01/2022',1,5),
('08/01/2022',1,2),
('17/01/2022',2,7),
('25/01/2022',2,7),
('15/02/2022',2,7)
-- CREATE A CALENDAR CTE
DECLARE #StartDate date = '20210101';
DECLARE #CutoffDate date = DATEADD(DAY, -1, DATEADD(YEAR, 2, #StartDate));
;WITH DateSeq(TheDate) AS
(
SELECT #StartDate
UNION ALL
SELECT DATEADD(dd,1,TheDate) FROM DateSeq
WHERE TheDate < #CutoffDate
)
-- CROSS JOIN OUR CALENDAR CTE TO OUR SOURCE DATA. DERIVED TABLE TO GET FIRST AND LAST OF EACH RANGE TO USE FOR JOIN
SELECT
ds.*
,SourceDataRangesByID.ID
,ISNULL(td.TheValue,0) AS TheValue
FROM
DateSeq ds
CROSS JOIN
(
SELECT
d.ID
,MIN(d.TheDate) AS MinDatePerID
,MAX(d.TheDate) AS MaxDatePerID
FROM #TheData d
GROUP BY d.ID
) SourceDataRangesByID
LEFT JOIN #TheData td ON td.id = SourceDataRangesByID.ID AND td.TheDate = ds.TheDate
WHERE ds.TheDate >= SourceDataRangesByID.MinDatePerID
AND ds.TheDate <= SourceDataRangesByID.MaxDatePerID
OPTION (MAXRECURSION 0);

Answer 3

try the generate_series to create a date table then right join with it and coalesce for the non null value
SELECT generate_series('2016-01-01', -- series start date
'2018-06-30', -- series end date
'1 day'::interval)::date AS day) AS daily_series
from mytable
See Generate_Series for TSQL
https://dba.stackexchange.com/questions/255165/does-ms-sql-server-have-generate-series-function
(Sql server 2022)
https://learn.microsoft.com/en-us/sql/t-sql/functions/generate-series-transact-sql?view=sql-server-ver16