MySQL 8.0

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create table lms_leads(id int, status varchar(10), assigned_to varchar(10), date datetime);
insert into lms_leads values
(1, 'open', 'Smith', '2018-08-26'),
(2, 'open', 'Drew', '2018-08-26'),
(3, 'new', 'Amit', '2018-08-26')
create table lms_leads_comments(id int, lead_id int, comment_data varchar(130), follow_up_time datetime);
insert into lms_leads_comments values
(1, 1, 'old task line2', '2018-08-27 14:18:26'),
(2, 2, 'old task line1', '2018-08-27 14:18:26'),
(3, 1, 'new task line1', '2018-08-27 17:18:00'),
(4, 2, 'new task line3', '2018-09-27 20:18:26'),
(5, 2, 'old task line2', '2018-08-27 21:18:26');
SELECT *
FROM (SELECT l.*, c.comment_data, c.follow_up_time,
         ROW_NUMBER() OVER(PARTITION BY l.id ORDER BY c.follow_up_time DESC) AS rn
      FROM lms_leads l 
      LEFT join lms_leads_comments as c ON l.id=c.lead_id) s
WHERE rn = 1;


id
status
assigned_to
date
comment_data
follow_up_time
rn


1
open
Smith
2018-08-26 00:00:00
new task line1
2018-08-27 17:18:00
1

2
open
Drew
2018-08-26 00:00:00
new task line3
2018-09-27 20:18:26
1

3
new
Amit
2018-08-26 00:00:00
null
null
1

id	status	assigned_to	date	comment_data	follow_up_time	rn
1	open	Smith	2018-08-26 00:00:00	new task line1	2018-08-27 17:18:00	1
2	open	Drew	2018-08-26 00:00:00	new task line3	2018-09-27 20:18:26	1
3	new	Amit	2018-08-26 00:00:00	null	null	1