SQL Server 2019

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create table t (starttime time(2), endtime time(2));
insert into t (starttime, endtime) values
  ('12:00:00', '12:34:56.789'),
  ('13:00:00', '13:34:56.789');
2 rows affected

select * from t;

starttime
endtime

12:00:00.00
12:34:56.79

13:00:00.00
13:34:56.79

SELECT FORMAT(startTime, 'hh\:mm') as startTime FROM t

startTime

12:00

13:00