일자 및 시간 정보의 저장 형태가 어떻게 되나요?
일자 및 시간이 한개 컬럼에 함께 저장되는지?
일자 및 시간이 두개 컬럼에 나뉘어 저장하는지?
DATE 타입인지? VARCHAR2 타입인지?
varchar2 타입의 경우 저장 포멧이 어떻게 되는지?

-- 5분 단위로 가정하고 해봤는데 지저분하고 구멍이 많아보이네요..;;
-- 고려안된 부분이 많습니다(날짜변경, 10분 이하 휴식 등)
-- 이런식으로도 가능은 하다 정도만 참고하시면 좋을 것 같습니다.

WITH t1(f, t) AS (
SELECT '01:00', '03:30' FROM dual
)
, t2(f, t) AS (
SELECT '01:50', '02:00' FROM dual UNION ALL
SELECT '02:50', '03:05' FROM dual 
)

SELECT TO_CHAR(MIN(a), 'hh24:mi') || ' ~ ' || TO_CHAR(MAX(a), 'hh24:mi') || ' 작업' ft
FROM 
(
	SELECT a, SUM(gb) OVER(ORDER BY a) gb
	FROM 
	(
		SELECT a, DECODE(a, (LAG(a, 1) OVER(ORDER BY 1)) + TO_DSINTERVAL('000 00:05:00'), 0, 1) gb
		FROM 
		(
		SELECT TO_TIMESTAMP(t1.f, 'hh24:mi') + TO_DSINTERVAL('000 00:05:00') * (lv - 1) a
		FROM t1, (SELECT LEVEL lv FROM dual CONNECT BY LEVEL <= 300) tmp
		WHERE tmp.lv <= (extract(hour FROM TO_TIMESTAMP(t1.t, 'hh24:mi') - TO_TIMESTAMP(t1.f, 'hh24:mi')) * 12 + extract(minute FROM TO_TIMESTAMP(t1.t, 'hh24:mi') - TO_TIMESTAMP(t1.f, 'hh24:mi')) / 5) + 1
		MINUS 
		SELECT b
		FROM 
		(
			SELECT TO_TIMESTAMP(t2.f, 'hh24:mi') + TO_DSINTERVAL('000 00:05:00') * (lv - 1) b, lv, ROW_NUMBER() OVER(PARTITION BY t2.f ORDER BY lv desc) lv2
			FROM t2, (SELECT LEVEL lv FROM dual CONNECT BY LEVEL <= 300) tmp
			WHERE tmp.lv <= (extract(hour FROM TO_TIMESTAMP(t2.t, 'hh24:mi') - TO_TIMESTAMP(t2.f, 'hh24:mi')) * 12 + extract(minute FROM TO_TIMESTAMP(t2.t, 'hh24:mi') - TO_TIMESTAMP(t2.f, 'hh24:mi')) / 5) + 1
		)
		WHERE lv <> 1 AND lv2 <> 1
		)
	)
)
GROUP BY gb
UNION ALL 
SELECT f || ' ~ ' || t || ' 휴식'
FROM t2
ORDER BY 1

작업 시간 관리가 작업자 별로 이루어 지는지? 일괄 적용되는지?
휴식 시간 관리가 작업자 별로 이루어 지는지? 일괄 적용되는지?

WITH work_t AS
(
SELECT '20200210' dt, '0100' stm, '0330' etm FROM dual
)
, rest_t AS
(
SELECT '20200210' dt, '0150' stm, '0200' etm FROM dual
UNION ALL SELECT '20200210', '0250', '0305' FROM dual
)
SELECT *
  FROM (SELECT dt
             , stm
             , LEAD(stm) OVER(ORDER BY stm) etm
             , gb
          FROM (SELECT dt, stm, '작업' gb FROM work_t
                 UNION ALL
                SELECT dt, etm, '종료' gb FROM work_t
                 UNION ALL
                SELECT dt, stm, '휴식' gb FROM rest_t
                 UNION ALL
                SELECT dt, etm, '작업' gb FROM rest_t
                )
         WHERE dt = '20200210'
        )
 WHERE gb != '종료'
;