Първо:имали сте два атрибута за един и същи product_id =1, променете таблицата product_attributes
по този начин -
INSERT INTO `product_attributes` (`product_id`,`type`,`value`) VALUES
(1,1,'blue'),
(1,2,'shirt'),
(2,1,'green'),
(2,2,'pants');
Тогава опитайте този -
SET @sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'MAX(IF(pat.name = ''', name, ''', pa.value, NULL)) AS ', name
)
) INTO @sql
FROM product_attribute_types;
SET @sql = CONCAT('SELECT pa.product_id, ', @sql, ' FROM product_attributes pa INNER JOIN product_attribute_types pat ON pa.type = pat.id GROUP BY pa.product_id');
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
Резултат:
+------------+-------+-------+
| product_id | color | name |
+------------+-------+-------+
| 1 | blue | shirt |
| 2 | green | pants |
+------------+-------+-------+
Добавете филтър WHERE, ако е необходимо.