Add Datatime and Time together and convert it in text - sql

Question

I need to add my work times together and after 10+ hours I have no idea how I should do this.
The tables look like this:
adrID wrk_Start wrk_End wrk_Pause
10 01-04-2020 10:00:00 01-04-2020 18:00:00 00:00:00
10 03-04-2020 10:00:00 03-04-2020 17:30:00 00:30:00
10 06-04-2020 12:00:00 06-04-2020 14:00:00 00:00:00
10 12-04-2020 09:00:00 12-04-2020 16:50:00 00:30:00
The result should be: 23:30 , mine is 5:00:27
The code is working only if I use little intervals like 10.04.2020 - 12.04.2020 and when I use bigger intervals or intervals that are in the future (today we have 17.04 and I use for ex. 10.04 - 20.04) is not working.
DECLARE #FromDate DATETIME = '01-04-2020 10:00:00';
DECLARE #ToDate DATETIME = '20-04-2020 17:00:00';
DECLARE #user INT = 10;
select convert(varchar, DATEADD(ss, sum(isnull(datediff(second, wrk_Start, wrk_End), 0)), 0), 108)
from worktime
where
wrk_adrID = #wrk_Name and
wrk_Start >= #wrk_FromDate and
wrk_End <= #wrk_ToDate

Answer 1

It is normally best to save the dates and time in mysql format, else it gets to much more code:
Your text has to be converted to dates with again get to seconds and finally back to a readable time.
First comes the mysql version, which had tagged false, and lower you find aSQL SERVER version, which is sowhat more complicated
SELECT
SEC_TO_TIME(SUM(TIMESTAMPDIFF(SECOND,STR_TO_DATE(`wrk_Start`,'%d-%m-%Y %k:%i:%s')
,STR_TO_DATE(`wrk_End`,'%d-%m-%Y %k:%i:%s'))
- TIME_TO_SEC(`wrk_Pause`)))
FROM
worktime;
Schema (MySQL v5.7)
CREATE TABLE worktime (
`wrk_Start` VARCHAR(19),
`wrk_End` VARCHAR(19),
`wrk_Pause` Time
);
INSERT INTO worktime
(`wrk_Start`, `wrk_End`, `wrk_Pause`)
VALUES
('01-04-2020 10:00:00', '01-04-2020 18:00:00', '00:00:00'),
('03-04-2020 10:00:00', '03-04-2020 17:30:00', '00:30:00'),
('06-04-2020 12:00:00', '06-04-2020 14:00:00', '00:00:00'),
('12-04-2020 09:00:00', '12-04-2020 16:50:00', '00:30:00');
Query #1
SELECT
SEC_TO_TIME(SUM(TIMESTAMPDIFF(SECOND,STR_TO_DATE(`wrk_Start`,'%d-%m-%Y %k:%i:%s')
,STR_TO_DATE(`wrk_End`,'%d-%m-%Y %k:%i:%s'))
- TIME_TO_SEC(`wrk_Pause`)))
FROM
worktime;
| SEC_TO_TIME(SUM(TIMESTAMPDIFF(SECOND,STR_TO_DATE(`wrk_Start`,'%d-%m-%Y %k:%i:%s')
,STR_TO_DATE(`wrk_End`,'%d-%m-%Y %k:%i:%s'))
- TIME_TO_SEC(`wrk_Pause`))) |
| --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 24:20:00 |
View on DB Fiddle
SQL SERVER
CREATE TABLE worktime (
wrk_Start nvarchar(19),
wrk_End nvarchar(19),
wrk_Pause nvarchar(8)
);
INSERT INTO worktime
(wrk_Start, wrk_End, wrk_Pause)
VALUES
('01-04-2020 10:00:00', '01-04-2020 18:00:00', '00:00:00'),
('03-04-2020 10:00:00', '03-04-2020 17:30:00', '00:30:00'),
('06-04-2020 12:00:00', '06-04-2020 14:00:00', '00:00:00'),
('12-04-2020 09:00:00', '12-04-2020 16:50:00', '00:30:00');
GO
4 rows affected
SELECT
(SUM(DATEDIFF(second,CONVERT(DATETIME,[wrk_Start]),
CONVERT(DATETIME,[wrk_End])) -
DATEDIFF(second,'00:00:00',[wrk_Pause]))) wrktime
FROM
worktime;
GO
| wrktime |
| ------: |
| 87600 |
DECLARE #seconds AS int = 896434;
SELECT CONVERT(varchar, (SUM(DATEDIFF(second,CONVERT(DATETIME,[wrk_Start]),
CONVERT(DATETIME,[wrk_End])) -
DATEDIFF(second,'00:00:00',[wrk_Pause]))) / 86400 ) + ':' + -- Days
CONVERT(varchar, DATEADD(ms, ( (SUM(DATEDIFF(second,CONVERT(DATETIME,[wrk_Start]),
CONVERT(DATETIME,[wrk_End])) -
DATEDIFF(second,'00:00:00',[wrk_Pause]))) % 86400 ) * 1000, 0), 108)
as "orktime"
FROM
worktime;
GO
| orktime |
| :--------- |
| 1:00:20:00 |
db<>fiddle here

Answer 2

First, don't try to convert the value back to a time -- SQL Server does not allow times that exceed 24 hours.
I would go for decimal hours. That would be:
select adrid,
(sum(datediff(second, wrk_start, wrk_end))-
sum(datediff(second, '00:00:00', wrk_pause))
) / (60.0 * 60) as decimal_hours
from worktime
group by adrid;
Here is a db<>fiddle.