some todas as suas pausas que ocorrem durante os tempos e, em seguida, subtraia o resultado da função timediff/time_to_sec
SELECT TIME_TO_SEC(TIMEDIFF('17:00:00', '09:00:00')) -- 28800
SELECT TIME_TO_SEC(TIMEDIFF('12:30:00', '12:00:00')) -- 1800
SELECT TIME_TO_SEC(TIMEDIFF('10:30:00', '10:15:00')) -- 900
-- 26100
Assumindo esta estrutura:
CREATE TABLE work_unit (
id INT NOT NULL,
initial_time TIME,
final_time TIME
)
CREATE TABLE break (
id INT NOT NULL,
initial_time TIME,
final_time TIME
)
INSERT work_unit VALUES (1, '09:00:00', '17:00:00')
INSERT break VALUES (1, '10:00:00', '10:15:00')
INSERT break VALUES (2, '12:00:00', '12:30:00')
Você pode calculá-lo com a próxima consulta:
SELECT *, TIME_TO_SEC(TIMEDIFF(final_time, initial_time)) total_time
, (SELECT SUM(
TIME_TO_SEC(TIMEDIFF(b.final_time, b.initial_time)))
FROM break b
WHERE (b.initial_time BETWEEN work_unit.initial_time AND work_unit.final_time) OR (b.final_time BETWEEN work_unit.initial_time AND work_unit.final_time)
) breaks
FROM work_unit
