How to get the difference between two times with SQL Server? - sql-server

Question

I have the following two column with Time values
;WITH cte AS (
SELECT *
FROM (VALUES
('08:00:00','18:30:00'),
('20:00:00','08:00:00'),
('18:30:00','06:00:00'),
('08:00:00','18:30:00')) as t(time1, time2)
)
How can I get the following difference values:
result
10.5
12
11.5
10.5
I tried with DATEDIFF but I am never able to get a true values especially for the case from 18:30 to 6:00
I tried like this, but does not work for this case(8:30 to 6:00) ...
CASE
WHEN GirisSaati > CikisSaati THEN cast( DATEDIFF(MINUTE, cast(CikisSaati as time ), cast(GirisSaati as time ))as float) / 60
WHEN GirisSaati <= CikisSaati THEN cast( DATEDIFF(MINUTE,cast( GirisSaati as time ), cast(CikisSaati as time ) )as float) /60
END
Hope to find help, thanks ...

Answer 1

This is because you are dividing by 60, an integer. This will return an integer result. Instead try dividing by a numeric:
Example
DECLARE #Time1 TIME(0) = '08:00:00';
DECLARE #Time2 TIME(0) = '18:30:00';
SELECT
DATEDIFF(MINUTE, #Time1, #Time2) / 60 AS Incorrect,
DATEDIFF(MINUTE, #Time1, #Time2) / 60.0 AS Correct
;
Result
Incorrect Correct
10 10.500000
This is a consequence of data type precedence. From MSDN:
When an operator combines two expressions of different data types, the
rules for data type precedence specify that the data type with the
lower precedence is converted to the data type with the higher
precedence. If the conversion is not a supported implicit conversion,
an error is returned. When both operand expressions have the same data
type, the result of the operation has that data type.
In this case INT has the highest precedence.
Alternatively you could use CAST to explicitly set the data type: CAST(60 AS DECIMAL(18,2)).

Answer 2

Here is how you can do it:
DECLARE #t table(time1 time, time2 time)
INSERT #t values
('08:00','18:30'),
('20:00','08:00'),
('18:30','06:00'),
('08:00','18:30')
;WITH CTE as
(
SELECT
time1, time2,
CASE WHEN time2 < time1 THEN 1 ELSE 0 END
+ CAST(time2 as datetime) - CAST(time1 as datetime) diff
FROM #t
)
SELECT
time1,
time2,
cast(diff as time) timediff,
cast(diff as float) * 24 decimaldiff
FROM CTE
Result:
time1 time2 timediff decimaldiff
08:00 18:30 10:30 10.5
20:00 08:00 12:00 12
18:30 06:00 11:30 11.5
08:00 18:30 10:30 10.5

Answer 3

I found another option...
Step 1 -> Create this SQL function
CREATE FUNCTION [dbo].[get_TimeDefferance_hh_mm_ss]
(
-- Add the parameters for the function here
#FromTime time,#ToTime time
)
RETURNS time
AS
BEGIN
declare #totalsec decimal(10,2)= datediff(SECOND,#FromTime,#ToTime);
declare #secondPart int= #totalsec%60
--select #secondPart As secondpart
declare #totalminsOnly int= (#totalsec-#secondPart)/60
declare #MinsPart int=#totalminsOnly%60
--select #MinsPart AS minsPart
declare #totalHoursOnly int= (#totalminsOnly-#MinsPart)/60
--select #totalHoursOnly AS totalhoursonly
-- Return the result of the function
RETURN cast(#totalHoursOnly AS varchar(50))+':'+cast(#MinsPart as varchar(50))+':'+cast(#secondPart as varchar(50))
END
Step 2->Go to new query and check is it working..
declare #FromTime time='2:30:41';
declare #ToTime time='4:20:30';
declare #timeDiff time= **dbo.get_TimeDefferance_hh_mm_ss(#FromTime,#ToTime)**
select #timeDiff
output---
01:49:49.0000000

Answer 4

Maybe it is a 'bit' later, but I will post my solution in order to help someone else.
set #from = '10:15';
set #to = '12:30';
select (time_to_sec(timediff(#to, #from))/3600);
Output is 2.2500