Schema (PostgreSQL v12)
CREATE TABLE test (ts timestamp, email varchar, title varchar);
insert into test values
('2017-01-01', 'me@me.com', 'Old title'),
('2017-01-02', 'me@me.com', null),
('2017-01-03', 'me@me.com', 'New Title'),
('2017-01-04', 'me@me.com', null),
('2017-01-05', 'me@me.com', null),
('2017-01-06', 'me@me.com', 'Newer Title'),