How avoid negative numbers during datediff - sql-server

Have table where have time like : 15:30 , want select data from table in 15 minute interval but only possitive, I try :
select id from myTbl
where type = 2 and DATEDIFF(mi,my_time,LEFT(CAST(GETDATE() as time),5)) <= 15
For example if my_time = 15:55 and LEFT(CAST(GETDATE() as time),5)) = 16:45 in response i have -50 and its <= 15 but i need comparison only possitive , when i try ABS it dont help me because when time in response is -14 ABS take it +14 and its <=15 . So i have 28 minute interval (-14 and 14). Is it possible tu avoid all negative numbers ? and comparison only if it is possitive

select id
from myTbl
where type = 2
and DATEDIFF(mi,my_time,LEFT(CAST(GETDATE() as time),5)) <= 15
and DATEDIFF(mi,my_time,LEFT(CAST(GETDATE() as time),5)) >=0

A much better approach would be some thing like ...
SELECT id
FROM myTbl
WHERE [TYPE] = 2
AND my_time >= CAST(DATEADD(MINUTE, -15, GETDATE()) AS TIME)
AND my_time <= CAST(GETDATE() AS TIME)
Avoid using DATEDIFF and other scalar functions on your columns in where clause, as it will not allow query optimizer to make use of any indexes even if there is an index that query can benefit from , Read this article for more information SARGable functions in SQL Server

Related

SQL: How to count distinct for all hourly periods in a day

I have a table of hotel data like this:
Room_ID
Check_in_time
Check_out_time
123
2021-10-01 01:02:03
2021-10-01 02:03:04
I would like to do a count of how many rooms were were checked in during each hour throughout a day (even if the room was checked in for 1 minute during the hour it still counts), so an output that look like this:
Time period
Number of rooms
09:00-10:00
10
10:00-11:00
12
..
..
There are a couple of other 'where' conditions but this is the crux of the problem. I have so far managed to write a query that can count unique room ID by specifying the hourly window:
select count (distinct room_id)
from data
where check_out_time > 9am and check_in_time < 10am
But how do I do this for each of the 24 hourly windows without repeating the same query 24 times? Hopefully something that can be later adapted into half hour intervals, or even minutes. I'm using Sigma in case that matters. Thanks in advance!
In Snowflake, I'd leverage a DATE_TRUNC function. If your dataset is very large, this will likely perform much better than any of the BETWEEN type of filtering that the OP and other answers are using.
select date_trunc('hour',check_out_time) as check_out_hour
, count (distinct room_id) as cnt
from data
group by 1;
If you needed to parse it out by day and time, you could add that, as well:
select date_trunc('day',check_out_time) as check_out_day
, date_trunc('hour',check_out_time) as check_out_hour
, count (distinct room_id) as cnt
from data
group by 1,2;
For reference:
https://docs.snowflake.com/en/sql-reference/functions/date_trunc.html
You may try the following:
A recursive CTE is used to generate the possible hours 0-23 (we could have also select distinct hours from your existing dataset but i did not want to assume that every hour was possibly booked and this may be a less expensive operation for this case to get all possible hours). A left join was then used to determine hours rooms were booked before aggregating this and counting the number of bookings each hour.
WITH recursive hours(hr) as (
select 0 as hr
union all
select hr + 1 from hours where hr < 23
)
select
concat(h.hr,':00-',(h.hr+1),':00') as time_period,
COUNT(DISTINCT r.room_id) as no_rooms
from hours h
left join room_times r on (
CAST(r.check_in_time AS DATE) = CAST(r.check_out_time AS DATE) AND
h.hr BETWEEN DATE_PART(hour,r.Check_in_time) AND DATE_PART(hour,r.Check_out_time)
) OR
(
CAST(r.check_in_time AS DATE) < CAST(r.check_out_time AS DATE) AND
(
h.hr >= DATE_PART(hour, r.Check_in_time) OR
h.hr <= DATE_PART(hour,r.Check_out_time)
)
)
GROUP BY h.hr
order by h.hr
See working db fiddle (using sql server instead) with the same logic and additional data and outputs to assist verification here.
Sample Data:
INSERT INTO room_times
(Room_ID, Check_in_time, Check_out_time)
VALUES
('123', '2021-10-01 01:02:03', '2021-10-01 03:03:04'),
('124', '2021-10-01 15:02:03', '2021-10-02 01:03:04');
Outputs:
time_period
no_rooms
0:00-1:00
1
1:00-2:00
2
2:00-3:00
1
3:00-4:00
1
4:00-5:00
0
5:00-6:00
0
6:00-7:00
0
7:00-8:00
0
8:00-9:00
0
9:00-10:00
0
10:00-11:00
0
11:00-12:00
0
12:00-13:00
0
13:00-14:00
0
14:00-15:00
0
15:00-16:00
1
16:00-17:00
1
17:00-18:00
1
18:00-19:00
1
19:00-20:00
1
20:00-21:00
1
21:00-22:00
1
22:00-23:00
1
23:00-24:00
1
Let me know if this works for you.

Can any one please tell me logic behind select DATENAME(month,29*5)

select DATENAME(month,29*5)
Can any one please tell me logic behind the above query.
How it always returns correct month name when provided month number as integer.
Datetime values in Sql server are stored on 8 bytes.
The first 4 bytes represents the date and the last 4 byte represents the time.
On the date part, date is stored as the number of days since 1900-01-01.
On the time part, it's the number of clock ticks since midnight.
There are 300 clock ticks per second, so a tick is 3.33333 milliseconds.
That's also the reason why datetime is only accurate to .003 of a second.
This query will hopefully help to explain:
SELECT CAST(0 As datetime) As Date_0,
29*5 As NumberOfDays,
CAST(29*5 as datetime) As TheDate,
DATENAME(month,29*5) As TheMonthName
Results:
Date_0 NumberOfDays TheDate TheMonthName
----------------------- ------------ ----------------------- ------------
1900-01-01 00:00:00.000 145 1900-05-26 00:00:00.000 May
As for the last part of your question, 29 (28 would work as well) is the magic number here - 30 is too big (May would be returned for 4 and 5) and 27 is too small - (September would be returned for 9 and 10).
Basically i'ts just math - get the number correctly so that each time you double it with any number between 1 and 12 will give you a number of days that sums up to a day that belongs to the correct month.
You can test it yourself using this script:
DECLARE #MagicNumber int = 28
;With cte as
(
select 1 as num
union all
select num + 1
from cte
where num < 12
)
SELECT num, DATENAME(month, #MagicNumber * num ) As TheMonthName
from cte
Just change the value of #MagicNumber and see the results you get.
I think I will able to explain.
The default year-month-day for any date data type is 1900-01-01. If we consider above select query, it add 29*5 days into default date and gives the MONTHNAME.
Select DATENAME(month,29*5)
Now understand the DATENAME
DateName - Returns a character string that represents the specified datepart of the specified date. Its have different -2 argument and give the different-2 result as per datepart.
Argument 1 - Is the part of the date to return.
Argument 2 - Is a any date (Is an expression that can be resolved to a
time, date, smalldatetime, datetime, datetime2, or datetimeoffset
value.)
Here we given month as a first argument. Which means it return monthname.
The calculation of 29*5 gives 145 answer and if we simply cast into date it consider as a days and calculate as 1900-01-01 + 145 and gives the date 1900-05-26 00:00:00.000.
Means if we get the month of this will give the 5 - MAY as a answer.
Execute this query and check the answer for the above logic.
Select DATENAME(month,29*5), (29*5) , DATENAME(month, '12:10:30.123'), DATENAME(month, getdate())
select cast (145 as datetime)
DECLARE #t datetime = '12:10:30.123';
SELECT DATENAME(month, 29*5), 145/30.00;
Check for further.
MSDN Link
Convert Month Number to Month Name Function in SQL (check the #user275683 answer)
If you are simply want to show the month corresponding to month number then you should have to use like this.
declare #intMonth as int
set #intMonth = 5
Select DateName( month , DateAdd( month , #intMonth , -1 ))

Get hour from datetime and put "Days" in field

Using SQL Server, I have the following:
SELECT DATENAME(DW, DATEADD(DAY, 0, #mindate)) AS Day_of_Week ,
#crewon AS Crew_On ,
ISNULL(SUM(( CONVERT(NUMERIC(8, 2), C.FinishLength) / 2000 )), 0) AS Finished_Tons ,
ISNULL(SUM(CASE WHEN C.RepairCode LIKE '%A%'
THEN ( CONVERT(NUMERIC(8, 2), C.FinishLength)
/ 2000 )
END), 0) AS A_Tons
FROM NYS2SawPieces C
WHERE RIGHT(C.ShiftIdent, 1) = #crewon
AND C.ProdTime >= #mindate
AND C.ProdTime <= DATEADD(DAY, 1, #mindate)
I need to get just the "Hours" from ProdTime that are from 06 to 18 and put "Days" in the column. Hours outside that range would be "Nights".
Output would like this but add the column for shift.
Day_of_Week Crew_On Finished_Tons A_Tons Shift
Sunday A 0.000000 0.0000000 Days
Use a CASE statement to apply conditional logic to determine the output:
SELECT Col1, Col2,
CASE WHEN DATEPART(HOUR,C.ProdTime) BETWEEN 6 AND 18 THEN 'DAYS'
ELSE 'NIGHTS'
END AS Shift
FROM....
This will output a new column called Shift that will output DAYS if the value is between 6 and 8, otherwise it will output NIGHTS.
You can use the WHERE and between sql commands to help you filter your query by the hour, something along the lines of:
WHERE hour(your_datetime_field) between 6 and 18
The WHERE acts as a filter in selecting data that is returned in your query. The rest of the statement is giving the bounds for the hours you want your_datetime_field to be between.

DateTime in sql only comparing the time

ID DateTime Code
---------- -------------- ----------
58 2015-01-01 20:00:00 1111
58 2015-01-11 10:00:00 8523
58 2015-01-11 03:00:00 4555
58 2015-01-19 00:01:00 8888
9 2015-01-01 20:00:00 4444
how do i count the number of codes for a specific ID ignoring which date it is but it must be between 20:00:00 and 06:00:00
select count(code) as count from table 1 where ID='58' and DateTime between '20:00:00' and '06:00:00'
the expected output would be
count
3
SELECT count(code) as count
FROM table1
WHERE
ID='58' and
(CAST(DateTime as time) >= '20:00'
or CAST(DateTime as time) <= '06:00')
EDIT: John, I understand the issue. Here is a full solution to handle those cases:
In order to use variables:
DECLARE #HourBegin time = '07:00'
DECLARE #HourEnd time = '17:30'
SELECT count(code) as count
FROM table1
WHERE
ID='58' and
(CAST(DateTime as time) between #HourBegin and #HourEnd or
((CAST(DateTime as time) <= #HourEnd or
CAST(DateTime as time) >= #HourBegin) and
#HourBegin > #HourEnd)
)
Almost the same as previous answer, but with hours it looks nicer for me and might be you need DISTINCT code
SELECT count(DISTINCT code) as count
FROM table1
WHERE
ID='58' and
(DATEPART(HOUR,DateTime) >= 20
or DATEPART(HOUR,DateTime) < 6)
UPDATED: changed from <= 6 to < 6
Update
This answer applies to MySQL.
When I started writing the answer, the question was tagged mysql and sql-server. The OP edited it in the meantime.
This query should do what you want on MySQL.
SELECT count(code) AS `count`
FROM `table 1`
WHERE ID='58'
AND TIME(`DateTime`) NOT BETWEEN '06:00:01' AND '19:59:59'
The MySQL function TIME() extracts only the time component from a DATETIME value.
On version 5.7, MySQL added support for fractional seconds (up to 6 digits) on DATETIME columns. The query above will include the entries having time greater than 06:00:00 but smaller than 06:00:01 (events that happened during the first second after 6 AM sharp).
For MySQL 5.7 and newer, the correct query is:
SELECT count(code) AS `count`
FROM `table 1`
WHERE ID='58'
AND (TIME(`DateTime`) <= '06:00:00' OR '20:00:00' <= TIME(`DateTime`))
I don't know about SQL Server.

TS SQL - group by minute

I have a table with timestamps. What is the proper query to get the records counts for each minute for the last hour.
I.e. if now is 2:25, I want to know how many record were between 1:25 and 1:26, 1:26 and 1:27, and so on, so I have 60 results.
This will return a count of results for each minute (where you have records) in the last hour
SELECT DATEPART(n, time_stamp) AS minute, COUNT(*) as results
FROM table_name
WHERE time_stamp > DATEADD(hh, -1, GETDATE())
GROUP BY DATEPART(n, time_stamp)
This may return less than 60 results, depending on the data. If you have to have 60 results, the query is slightly different. This uses a Common Table Expression to generate a list of 60 numbers and a correlated sub-query to get the results for each minute:
WITH numbers ( num ) AS (
SELECT 1 UNION ALL
SELECT 1 + num FROM numbers WHERE num < 60 )
SELECT num AS minute,
(SELECT COUNT(*) AS results
FROM table_name
WHERE DATEPART(n, time_stamp) = num
AND time_stamp > DATEADD(hh, -1, GETDATE())
FROM numbers
To see the results, replace DATEADD(hh, -1, GETDATE()) with DATEADD(mi, -15, GETDATE()) and you'll get the results for the last 15 minutes and 0 for other minutes.
This is an alternative I have found useful for determining how many records are inserted or updated per minute. The nice thing about having your date format as a variable up front is that you can easily change it to analyze per hour instead. Hope this helps!
DECLARE #dateFormat as varchar(max) = 'yyyy-MM-dd HH:mm'
SELECT format(timeColumn, #dateFormat) AS minute, COUNT(*) as results
FROM yourTable
WHERE timeColumn > DATEADD(hh, -1, GETDATE())
GROUP BY format(timeColumn, #dateFormat)
ORDER BY 1
As you edited the question, I edit my answer. If I have understood you correctly, you want to look only at the past hour - that is, a timespan from one hour before the request is made to the current time. This is how I'd do it:
SELECT
COUNT(yourTimeStamp)
FROM yourTable
WHERE DATEADD('hh', -1, GetDate()) <= yourTimeStamp
AND yourTimeStamp < GetDate()
GROUP BY DATEPART('mm', yourTimeStamp)
I am not entirely sure that the syntax is exact. When coding in MSSQL, I would use the CURRENT_TIMESTAMP for the current time, MINUTE instead of DATEPART etc, but you get the idea for the solution.
DATEPART is what you're looking for:
declare #times table
(
someTime datetime
)
INSERT INTO #Times (sometime) values ('jan 12 2008 12:23')
INSERT INTO #Times (sometime) values ('jan 12 2008 12:34')
INSERT INTO #Times (sometime) values ('jan 12 2008 12:35')
INSERT INTO #Times (sometime) values ('jan 12 2008 12:25')
INSERT INTO #Times (sometime) values ('jan 12 2008 12:02')
INSERT INTO #Times (sometime) values ('jan 12 2008 12:09')
INSERT INTO #Times (sometime) values ('jan 12 2008 12:35')
select DATEPART(mi,sometime) AS Minute, count(*) AS NumOccurances
from #Times
WHERE SomeTime BETWEEN #Lower AND #Upper
GROUP BY DATEPART(mi, sometime)
order by NumOccurances DESC
Result:
Minute NumOccurances
35 2
2 1
9 1
23 1
25 1
34 1
If you want to group results by minute, then you can use a formatted string. This will group by number of minutes since 1/1/1900 not minute within day.
WITH formatted AS (
SELECT FORMAT(<your_datetime_column>, 'yyyy-MM-dd HH:mm') AS minute_text
FROM <your_table>
)
SELECT minute_text, COUNT(*) AS number_of_rows
FROM formatted
GROUP BY minute_text
ORDER BY 1 DESC
Here's my fixed up version of Robin's answer. I made it output the errors in the correct order and output the time as well instead of just the number which isn't super useful if you're charting this out.
WITH numbers ( num ) AS (
SELECT 1 UNION ALL
SELECT 1 + num FROM numbers WHERE num < 60 )
SELECT (SELECT DATEADD(n, -num, GETDATE())) AS TimeStamp,
(SELECT COUNT(*) AS results
FROM ErrorLogs
WHERE DATEPART(n, TimeStamp) = DATEPART(n, DATEADD(n, -num, GETDATE()))
AND TimeStamp > DATEADD(hh, -1, GETDATE())) as Count
FROM numbers
SELECT COUNT (TS) from TABLE where TABLE.TS BETWEEN(starttime, endtime)

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