MySQL 8.0

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CREATE TABLE `document_signature` (
  `id` INT,
  `document_id` INT,
  `employee_id` INT,
  `user_id` INT,
  `order` INT,
  `status` VARCHAR(255));

INSERT INTO `document_signature` VALUES
(1,1,2,NULL,0,'SIGNED'),
(2,1,3,NULL,1,'NOTSIGNED'),
(3,1,4,NULL,1,'NOTSIGNED'),
(4,2,3,NULL,0,'NOTSIGNED'),
(5,3,NULL,1,0,'SIGNED'),
(6,3,1,NULL,0,'NOTSIGNED');

SELECT *
FROM document_signature;

Records: 6  Duplicates: 0  Warnings: 0




id
document_id
employee_id
user_id
order
status


1
1
2
null
0
SIGNED

2
1
3
null
1
NOTSIGNED

3
1
4
null
1
NOTSIGNED

4
2
3
null
0
NOTSIGNED

5
3
null
1
0
SIGNED

6
3
1
null
0
NOTSIGNED


INSERT INTO `document_signature` VALUES
(7,1,3,NULL,2,'NOTSIGNED'),
(8,2,4,NULL,2,'NOTSIGNED');

SELECT *
FROM document_signature;

Records: 2  Duplicates: 0  Warnings: 0




id
document_id
employee_id
user_id
order
status


1
1
2
null
0
SIGNED

2
1
3
null
1
NOTSIGNED

3
1
4
null
1
NOTSIGNED

4
2
3
null
0
NOTSIGNED

5
3
null
1
0
SIGNED

6
3
1
null
0
NOTSIGNED

7
1
3
null
2
NOTSIGNED

8
2
4
null
2
NOTSIGNED


SELECT *,
       MIN(`order`) OVER (PARTITION BY document_id) AS min_ord
   FROM document_signature
  WHERE status='NOTSIGNED'
ORDER by id


id
document_id
employee_id
user_id
order
status
min_ord


2
1
3
null
1
NOTSIGNED
1

3
1
4
null
1
NOTSIGNED
1

4
2
3
null
0
NOTSIGNED
0

6
3
1
null
0
NOTSIGNED
0

7
1
3
null
2
NOTSIGNED
1

8
2
4
null
2
NOTSIGNED
0


SELECT *
  FROM
(SELECT *,
       MIN(`order`) OVER (PARTITION BY document_id) AS min_ord
   FROM document_signature
  WHERE status='NOTSIGNED') s
WHERE s.`order`=s.min_ord;


id
document_id
employee_id
user_id
order
status
min_ord


2
1
3
null
1
NOTSIGNED
1

3
1
4
null
1
NOTSIGNED
1

4
2
3
null
0
NOTSIGNED
0

6
3
1
null
0
NOTSIGNED
0


WITH cte AS  
  (SELECT *,
       MIN(`order`) OVER (PARTITION BY document_id) AS min_ord
   FROM document_signature
  WHERE status='NOTSIGNED') 
SELECT * FROM cte
   WHERE `order`=min_ord;


id
document_id
employee_id
user_id
order
status
min_ord


2
1
3
null
1
NOTSIGNED
1

3
1
4
null
1
NOTSIGNED
1

4
2
3
null
0
NOTSIGNED
0

6
3
1
null
0
NOTSIGNED
0

id	document_id	employee_id	user_id	order	status
1	1	2	null	0	SIGNED
2	1	3	null	1	NOTSIGNED
3	1	4	null	1	NOTSIGNED
4	2	3	null	0	NOTSIGNED
5	3	null	1	0	SIGNED
6	3	1	null	0	NOTSIGNED