DROP TABLE IF EXISTS transaction CASCADE;

CREATE TABLE transaction (
    times INTEGER PRIMARY KEY,
    ta Integer,
    object VARCHAR(1),
        access VARCHAR(5),
        CHECK(access = 'read' OR access = 'write')
);

INSERT INTO transaction
(times, ta, object, access)
VALUES
(1, 1, 'A', 'read'),
(2, 2, 'B', 'read'),
(3, 2, 'B', 'write'),
(4, 3, 'A', 'read'),
(5, 3, 'C', 'write'),
(6, 2, 'C', 'read'),
(7, 1, 'B', 'read'),
(8, 3, 'D', 'write');


SELECT a.object, a.times AS A_Time, a.ta AS A_Trans, b.times AS B_Time, b.ta AS B_Trans
FROM transaction a
JOIN transaction b ON a.object = b.object
JOIN transaction c ON a.ta = c.ta
WHERE a.ta <> b.ta
AND b.times > a.times
AND c.times > b.times
;
WITH Startend AS (SELECT MIN(a.times) AS start, MAX(a.times) AS ende, a.ta
  FROM transaction  a JOIN transaction b USING (ta)
  GROUP BY ta),
 r AS (
  SELECT 1 AS times, 1 AS ta, 'A'::VARCHAR AS object
  UNION ALL
  SELECT b.times, b.ta, b.object
  FROM r
  JOIN transaction b on b.times > r.times )

Select *
from startend;