How to repeat values in a table in SQL Server? - sql

Question

I have a table in Microsoft SQL Server that logged some values on data change triggers. Now, in order to display some graphs, I would like to get (or repeat) a value per 10 minutes from each column(for example).
I would try to avoid, if possible, an INSERT command modifying the table itself.
Original table:
Time Stamp---- | A | B | C |
---------------+---+---+---+
01-01-19 10:20 | 1 | 0 | 0 |
01-01-19 15:30 | 0 | 0 | 1 |
01-01-19 22:50 | 0 | 1 | 0 |
02-01-19 01:40 | 1 | 0 | 0 |
...
Result I would like to achieve:
Time Stamp---- | A | B | C |
---------------+---+---+---+
01-01-19 10:20 | 1 | 0 | 0 |
01-01-19 10:30 | 1 | 0 | 0 |
01-01-19 10:40 | 1 | 0 | 0 |
01-01-19 10:50 | 1 | 0 | 0 |
...
01-01-19 15:30 | 0 | 0 | 1 |
01-01-19 15:40 | 0 | 0 | 1 |
01-01-19 15:50 | 0 | 0 | 1 |
01-01-19 16:00 | 0 | 0 | 1 |
...

Answer 1

Assuming your dates are mm-dd-yy and times are hh:mm...
create table #Original (
[Time Stamp----] datetime2,
A int,
B int,
C int
)
insert #Original
values ({ts '2019-01-01 10:20:00.000'}, 1, 0, 0)
, ({ts '2019-01-01 15:30:00.000'}, 0, 0, 1)
, ({ts '2019-01-01 22:50:00.000'}, 0, 1, 0)
, ({ts '2019-01-02 01:40:00.000'}, 1, 0, 0)
;
with
boundaries as (
select min(o.[Time Stamp----]) as s
, dateadd(minute, 10, max(o.[Time Stamp----])) as e
from #Original o
),
timeslist as (
select 1 as i
, (select s from boundaries) as s
, (select s from boundaries) as d
union all
select t.i + 1
, t.s
, dateadd(minute, 10, d)
from timeslist t
where d < (select e from boundaries)
),
result as (
select
right('0' + cast(MONTH(t.d) as varchar(2)), 2) + '-' +
right('0' + cast(DAY(t.d) as varchar(2)), 2) + '-' +
right('0' + cast(year(t.d) % 100 as varchar(2)), 2) + ' ' +
right('0' + cast(datepart(hour, t.d) as varchar(2)), 2) + ':' +
right('0' + cast(datepart(minute, t.d) as varchar(2)), 2) as 'Time Stamp----'
, o2.A
, o2.B
, o2.C
from timeslist t
inner join (
select o.[Time Stamp----]
, o.A
, o.B
, o.C
, lead (o.[Time Stamp----], 1, dateadd(minute, 10, o.[Time Stamp----])) over (order by o.[Time Stamp----]) as OldTs
from #Original o
) o2 on o2.[Time Stamp----] <= t.d and o2.OldTs > t.d
)
select *
from result
order by [Time Stamp----]
drop table #Original

Answer 2

To select records with manufactured duplicates, try
SELECT Dateadd(mi, DQ.T,TimeStamp) as 'TimeStamp', A, B, C From YourTable
CROSS JOIN (Select 0 T UNION ALL
Select 10 T UNION ALL
Select 20 T UNION ALL
Select 30 T) DQ
or to insert duplicates, try
INSERT YourTable
SELECT Dateadd(mi, DQ.T,TimeStamp) as 'TimeStamp', A, B, C From YourTable
CROSS JOIN (
Select 10 T UNION ALL
Select 20 T UNION ALL
Select 30 T) DQ

Answer 3

Personally I recommend maling a "Time Table", but i do this on the fly here using a Tally. Anyway, I think this is what you're after?
USE Sandbox;
GO
CREATE TABLE dbo.YourTable ([timestamp] datetime2(0), --This is a bad name for a column, as timestamp means soemthing else in SQL Server
A bit,
B bit,
C bit);
INSERT INTO dbo.YourTable ([timestamp],
A,
B,
C)
VALUES ('2019-01-01T10:20:00',1,0,0),
('2019-01-01T15:30:00',0,0,1),
('2019-01-01T22:50:00',0,1,0),
('2019-01-02T01:40:00',1,0,0);
GO
WITH N AS
(SELECT N
FROM (VALUES(NULL),(NULL),(NULL),(NULL),(NULL),(NULL))N(N)),
Tally AS(
SELECT TOP(144) ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) -1 AS I
FROM N N1, N N2, N N3),
Times AS(
SELECT DATEADD(MINUTE,T.I * 10,CONVERT(time(0),'00:00:00')) AS TimeSlot
FROM Tally T),
DateTimes AS(
SELECT DISTINCT
CONVERT(datetime,CONVERT(date,YT.[timestamp])) + CONVERT(datetime,T.TimeSlot) AS DateTimeSlot
FROM dbo.YourTable YT
CROSS JOIN Times T),
Groups AS(
SELECT DT.DateTimeSlot,
CONVERT(tinyint,YT.A) AS A, --Can't aggregate Bits
CONVERT(tinyint,YT.B) AS B,
CONVERT(tinyint,YT.C) AS C,
COUNT(YT.A) OVER (ORDER BY DT.DateTimeSlot ASC ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS Grp
FROM DateTimes DT
LEFT JOIN dbo.YourTable YT ON DT.DateTimeSlot = YT.[timestamp])
SELECT G.DateTimeSlot,
MAX(G.A) OVER (PARTITION BY G.Grp) AS A,
MAX(G.B) OVER (PARTITION BY G.Grp) AS B,
MAX(G.C) OVER (PARTITION BY G.Grp) AS C
FROM Groups G
ORDER BY G.DateTimeSlot;
GO
DROP TABLE dbo.YourTable;

Answer 4

You can use SQL RECURSION and CROSS JOIN
SQL FIDDLE
Demo
declare #mytable as table(timestamp datetime,A int,B int,C int)
insert into #mytable values
('01-01-19 10:20',1,0,0),('01-01-19 15:30',0,0,1),
('01-01-19 22:50',0,1,0),('01-01-19 01:40',1,0,0)
;with cte as(
select 0 n
union all
select n+10 from cte where n+10 <40)
select dateadd(mi,n,timestamp)[TIMESTAMP],t1.A,t1.B,T1.C
from #mytable t1 cross join cte
order by timestamp