Mysql 5.7 - get multiple values from sub select - mysql

Question

In the query below I am "JOINING" another table where i.isPrimary > 0 and if all i.isPrimary are 0 I just get the first result.
The result set from the query is as expected, but I want to bring more values from each subselect.
I am getting the error: SQL Error (1241): Operand should contain 1 column(s).
How can this query be rewritten in order to get more results from each subselect?
Thanks
-- borrowed from https://stackoverflow.com/q/7745609/808921
CREATE TABLE IF NOT EXISTS `ResearchEntity` (
`id` int(6) unsigned NOT NULL,
`name` varchar(200) NOT NULL,
PRIMARY KEY (`id`)
) DEFAULT CHARSET=utf8;
INSERT INTO `ResearchEntity` (`id`, `name`) VALUES
('1', 'one'),
('2', 'two'),
('3', 'three');
CREATE TABLE IF NOT EXISTS `ProfileImageEntity` (
`id` int(6) unsigned NOT NULL,
`isPrimary` int(1) unsigned NOT NULL,
`value` varchar(200) NOT NULL,
`researchId` int(2) unsigned NOT NULL,
PRIMARY KEY (`id`)
) DEFAULT CHARSET=utf8;
INSERT INTO `ProfileImageEntity` (`id`,`isPrimary`, `value`,`researchId`) VALUES
('1', 0, 'not primary',1),
('2', 0, 'not primary',1),
('3', 1, 'primary!!!',1),
('4', 0, 'primary!!!',2),
('5', 0, 'not primary',2),
('6', 0, 'not primary',2)
;
CREATE TABLE IF NOT EXISTS `UserNameEntity` (
`id` int(6) unsigned NOT NULL,
`isPrimary` int(1) unsigned NOT NULL,
`value` varchar(200) NOT NULL,
`researchId` int(2) unsigned NOT NULL,
PRIMARY KEY (`id`)
) DEFAULT CHARSET=utf8;
INSERT INTO `UserNameEntity` (`id`,`isPrimary`, `value`,`researchId`) VALUES
('1', 0, 'first one, should be returned',1),
('2', 0, 'not primary',1),
('3', 0, 'primary',1),
('4', 1, 'primary',3),
('5', 0, 'not primary',3),
('6', 0, 'not primary',3);
SQL FIDDLE
: http://sqlfiddle.com/#!9/028218/1
SELECT r.*,
(SELECT i.id FROM ProfileImageEntity i WHERE i.researchId = r.id ORDER BY i.isPrimary DESC, i.id ASC LIMIT 1 ) AS primaryImageId,
(SELECT i.id FROM UserNameEntity i WHERE i.researchId = r.id ORDER BY i.isPrimary DESC, i.id ASC LIMIT 1 ) AS primaryImageId
FROM ResearchEntity r
ORDER BY id DESC;

Answer 1

What I understood from your question and comment that you want more columns from sub Query which is not possible. So try this query:
It is easy in MySql 8 but you are using MySql 5.7 where it a little bit tricky So try this:
select
t1.*,
t2.id AS primaryImageId,
t2.value AS primaryImageValue,
t3.id AS primaryUserId,
t3.value AS primaryUserValue
from ResearchEntity t1
left join (
SELECT *,
IF(researchId=#last,#_seq:=#_seq+1,#_seq:=1) AS rn,
#last:=researchId
FROM ProfileImageEntity , (SELECT #_seq:=1, #last:=0) r
ORDER BY researchId,isPrimary DESC, id ASC
) t2 on t1.id=t2.researchId and t2.rn=1
left join (
SELECT *,
IF(researchId=#last,#_seq:=#_seq+1,#_seq:=1) AS rn,
#last:=researchId
FROM UserNameEntity , (SELECT #_seq:=1, #last:=0) r
ORDER BY researchId,isPrimary DESC, id ASC
) t3 on t1.id=t3.researchId and t3.rn=1
order by t1.id
DEMO
In MySql 8 using row_number()
with cte as (
SELECT *,
row_number() over (partition by researchId ORDER BY isPrimary DESC, id ASC) rn
FROM ProfileImageEntity
),
cte1 as (
sELECT *,
row_number() over (partition by researchId ORDER BY isPrimary DESC, id ASC) rn
FROM UserNameEntity
)
select
t1.*,
t2.id AS primaryImageId,
t2.value AS primaryImageValue,
t3.id AS primaryUserId,
t3.value AS primaryUserValue
from ResearchEntity t1 left join cte t2 on t1.id=t2.researchId and t2.rn=1
left join cte1 t3 on t1.id=t3.researchId and t3.rn=1

Answer 2

try left join
SELECT r.*,i.id FROM ResearchEntity r left join ProfileImageEntity i on r.id = i.researchId
ORDER BY i.isPrimary,i.id DESC;

Answer 3

you just need to left join 2 times
SELECT r.*,i.id,j.id FROM ResearchEntity r left join ProfileImageEntity i on r.id = i.researchId left join UserNameEntity j on r.id=j.researchId ORDER BY i.isPrimary,i.id DESC;