MariaDB 10.3

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

select @@version;


@@version


10.3.32-MariaDB


CREATE TABLE `member` (
  `memberid` int(11) NOT NULL,
  `email` text
);
INSERT INTO member
(memberid, email)
VALUES(1038, 'abc@testing.comm');
CREATE TABLE `protocol` (
  `protocolid` int(11) NOT NULL,
  `createdby` int(11) NOT NULL,
  `status` varchar(256) DEFAULT NULL
) ;
CREATE TABLE `protocolpost` (
  `protocolid` int(11) NOT NULL,
  `protocolpostid` int(11) NOT NULL,
  `createdby` text
  ) ;
CREATE TABLE `protocolpostcomment` (
  `protocolpostcommentid` int(11) NOT NULL,
  `protocolpostid` int(11) NOT NULL,
  `commentedby` varchar(256) DEFAULT NULL,
  `hasfeedbackreplyviewed` tinyint(1) DEFAULT NULL
) ;
INSERT INTO protocol
(protocolid, createdby, status)
VALUES(3357, 1038, 'Published');
INSERT INTO protocolpost
            (protocolid,
             protocolpostid,
             createdby)
VALUES     (3357,
            304,
            'nwxaofrc@grr.la,');

INSERT INTO protocolpost
            (protocolid,
             protocolpostid,
             createdby)
VALUES     (3357,
            305,
            'nwxaofrc@tempemail.com,');

INSERT INTO protocolpost
            (protocolid,
             protocolpostid,
             createdby)
VALUES     (3357,
            306,
            '27june2020@yopmail.com,');

INSERT INTO protocolpost
            (protocolid,
             protocolpostid,
             createdby)
VALUES     (3357,
            306,
            '27june2020@yopmail.com,'); 
INSERT INTO protocolpostcomment
            (protocolpostcommentid,
             protocolpostid,
             commentedby,
             hasfeedbackreplyviewed)
VALUES     (420,
            304,
            'abc@testing.comm,',
            0);

INSERT INTO protocolpostcomment
            (protocolpostcommentid,
             protocolpostid,
             commentedby,
             hasfeedbackreplyviewed)
VALUES     (421,
            305,
            'abc@testing.comm,',
            0);

INSERT INTO protocolpostcomment
            (protocolpostcommentid,
             protocolpostid,
             commentedby,
             hasfeedbackreplyviewed)
VALUES     (422,
            306,
            'abc@testing.comm,',
            0);

INSERT INTO protocolpostcomment
            (protocolpostcommentid,
             protocolpostid,
             commentedby,
             hasfeedbackreplyviewed)
VALUES     (423,
            306,
            'nwxaofrc@tempemail.com,',
            0); 
select * from protocolpost;


protocolid
protocolpostid
createdby


3357
304
nwxaofrc@grr.la,

3357
305
nwxaofrc@tempemail.com,

3357
306
27june2020@yopmail.com,

3357
306
27june2020@yopmail.com,


SELECT email
                                                            FROM   member
                                                            WHERE
                                               memberid = 1038


email


abc@testing.comm


SELECT 
       protocols.*,
       protocolFeedbackReply.*,
       protocolfeedback.*
FROM   protocolpost AS protocolfeedback
       JOIN protocol AS protocols
         ON protocols.protocolid = protocolfeedback.protocolid
       JOIN protocolpostcomment AS protocolFeedbackReply
         ON protocolfeedback.protocolpostid =
            protocolFeedbackReply.protocolpostid
WHERE  protocols.createdby = 1038
       AND protocols.status = "published"
       AND protocolFeedbackReply.hasfeedbackreplyviewed = 0
       AND protocolFeedbackReply.commentedby NOT LIKE Concat('%', (SELECT email
                                                            FROM   member
                                                            WHERE
                                               memberid = 1038),
                                               '%'); 


protocolid
createdby
status
protocolpostcommentid
protocolpostid
commentedby
hasfeedbackreplyviewed
protocolid
protocolpostid
createdby


3357
1038
Published
423
306
nwxaofrc@tempemail.com,
0
3357
306
27june2020@yopmail.com,

3357
1038
Published
423
306
nwxaofrc@tempemail.com,
0
3357
306
27june2020@yopmail.com,

protocolid	protocolpostid	createdby
3357	304	nwxaofrc@grr.la,
3357	305	nwxaofrc@tempemail.com,
3357	306	27june2020@yopmail.com,
3357	306	27june2020@yopmail.com,

protocolid	createdby	status	protocolpostcommentid	protocolpostid	commentedby	hasfeedbackreplyviewed	protocolid	protocolpostid	createdby
3357	1038	Published	423	306	nwxaofrc@tempemail.com,	0	3357	306	27june2020@yopmail.com,
3357	1038	Published	423	306	nwxaofrc@tempemail.com,	0	3357	306	27june2020@yopmail.com,