我有3个具有以下架构的表：
需求类别
+----+--------+----------+
| id | name | category |
+----+--------+----------+
| 1 | Height | D |
| 2 | Age | D |
| 3 | Time | E |
+----+--------+----------+
项目要求
+----+----------------+-------------------+------------+
| id | requirement_id | requirement_value | project_id |
+----+----------------+-------------------+------------+
| 1 | 1 | Tall | 1 |
| 2 | 1 | Medium | 1 |
| 3 | 1 | Short | 1 |
| 4 | 2 | Young | 1 |
| 5 | 2 | Middle | 1 |
| 6 | 2 | Senior | 1 |
| 7 | 3 | Day | 1 |
| 8 | 3 | Night | 1 |
+----+----------------+-------------------+------------+
ProjectTestRequirements
+----+-------------+----------+------------------------+
| id | project_id | test_id | project_requirement_id |
+----+-------------+----------+------------------------+
| 1 | 1 | 1 | 1 |
| 2 | 1 | 1 | 5 |
| 3 | 1 | 1 | 8 |
+----+-------------+----------+------------------------+
ProjectTests
+----+-------------+----------+
| id | project_id | test_id |
+----+-------------+----------+
| 1 | 1 | 1 |
+----+-------------+----------+
我想要这样的输出：
+---------+--------+--------+-------+
| test_id | Height | Age | Time |
+---------+--------+--------+-------+
| 1 | Tall | Middle | Night |
+---------+--------+--------+-------+
我正在尝试使用laravel进行此操作，但我需要知道如何编写查询以获取共享的输出。
我尝试了以下
SET @sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'max(case when rc.name = ''',
name,
''' then pr.requirement_value end) AS ',
replace(name, ' ', '')
)
) INTO @sql
from requirement_categories;
SET @sql = CONCAT('
SELECT
ptr.test_id, ', @sql, '
from
project_test_requirements ptr
project_requirements pr,
requirement_categories rc,
project_test pt
where
ptr.test_id=pt.test_id
and
ptr.requirement_id = pr.id
and
rc.id = pr.requirement_id
group by
ptr.test_id
');
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
它抛出此错误：
16:11:54 PREPARE stmt FROM @sql Error Code: 1064. You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Group,max(case when rc.name = 'height' then pr.requirement_value end) AS height ' at line 2 0.000 sec