Postgres 11

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CREATE TABLE member (
    start_time timestamp
);

INSERT INTO member VALUES
('2014-12-31 23:59:59'),
('2015-01-01 00:00:00'),
('2015-05-23 12:34:56'),
('2015-12-31 23:59:59'),
('2016-01-01 00:00:00'),
('2016-05-23 12:34:56'),
('2017-11-01 05:23:52'),
('2020-06-23 14:27:56');

SELECT * FROM member
8 rows affected

start_time

2014-12-31 23:59:59

2015-01-01 00:00:00

2015-05-23 12:34:56

2015-12-31 23:59:59

2016-01-01 00:00:00

2016-05-23 12:34:56

2017-11-01 05:23:52

2020-06-23 14:27:56

SELECT
    *
FROM
    member
WHERE start_time::date BETWEEN '2015-01-01' AND '2015-12-31'

start_time

2015-01-01 00:00:00

2015-05-23 12:34:56

2015-12-31 23:59:59

SELECT
    *
FROM
    member
WHERE date_part('year', start_time) = 2015

start_time

2015-01-01 00:00:00

2015-05-23 12:34:56

2015-12-31 23:59:59