MySQL 8.0

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CREATE TABLE people( id INT, name VARCHAR(10), attribute_id INT );
INSERT INTO people VALUES
(1, 'Ken', 1),
(1, 'Ken', 2),
(1, 'Ken', 3),
(2, 'John', 4)

Records: 4  Duplicates: 0  Warnings: 0


CREATE TABLE attributes( id INT, attributes VARCHAR(10) );
INSERT INTO attributes VALUES
(1, 'Tall'),
(2, 'Slender'),
(3, 'Blonde'),
(4, 'Short')

Records: 4  Duplicates: 0  Warnings: 0


SELECT ID, Name, 
       MAX( CASE WHEN rn = 1 THEN attributes END ) AS attribute1, 
       MAX( CASE WHEN rn = 2 THEN attributes END ) AS attribute2,
       MAX( CASE WHEN rn = 3 THEN attributes END ) AS attribute3 
  FROM
    (
     SELECT p.ID, Name, attributes,
            ROW_NUMBER() OVER (PARTITION BY ID ORDER BY ID) AS rn
       FROM people AS p
       LEFT JOIN attributes AS a
         ON a.ID = p.attribute_ID
     ) AS pa
 GROUP BY ID, Name


ID
Name
attribute1
attribute2
attribute3


1
Ken
Tall
Slender
Blonde

2
John
Short
null
null


SET @sql = NULL;

SELECT GROUP_CONCAT(
           DISTINCT
              CONCAT(
                    'MAX(CASE WHEN rn =', rn,' THEN attributes END) AS attribute',rn
                    )
       )
  INTO @sql
  FROM 
  (
   SELECT DISTINCT ROW_NUMBER() OVER (PARTITION BY id) AS rn 
     FROM people 
    ORDER BY rn                 
  ) AS r;

SET @sql = CONCAT('SELECT ID, Name, ',@sql,
                   ' FROM
                      (
                       SELECT p.ID, Name, attributes,
                              ROW_NUMBER() OVER (PARTITION BY ID ORDER BY ID) AS rn
                         FROM people AS p
                         LEFT JOIN attributes AS a
                           ON a.ID = p.attribute_ID
                       ) AS pa
                    GROUP BY ID, Name'); 

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

Statement prepared




ID
Name
attribute1
attribute2
attribute3


1
Ken
Tall
Slender
Blonde

2
John
Short
null
null