How to generate this SQL query like pivot table - php

Question

I want to three table union to one query like a pivot table.
My main table name is products and two support tables name are code_keys and code_values
I have a main table name: products
+------------------+
| Field |
+------------------+
| productid |
| catpath |
| da |
| l0 |
| ig |
| des |
| notes |
| wire |
| lmm |
+------------------+
example data:
+-----------+------+------+------+
| productid | da | ig | des |
+-----------+------+------+------+
| 5 | 78 | 33 | 23 |
| 8 | 88 | 13 | 21 |
+-----------+------+------+------+
and 2 conf table names: code_keys. Store code structure.
+--------+
| Field |
+--------+
| codeid |
| title |
| codekey|
| format |
+--------+
example data:
+--------+----------------+
| codeid | title |
+--------+----------------+
| 2 | St Code |
| 3 | Rear Les |
+--------+----------------+
code_values
+-------+
| Field |
+-------+
| id |
| pid | -> Product ID
| codeid|
| value |
+-------+
and finally example data:
+----+------+--------+--------------+
| id | pid | codeid | value |
+----+------+--------+--------------+
| 9 | 5 | 2 | ST 102 200 R |
| 10 | 5 | 3 | 12 000 33 |
| 11 | 6 | 2 | ST 343 432 R |
| 12 | 6 | 3 | 34 343 24 |
| 15 | 8 | 2 | ST 100 101 R |
| 16 | 8 | 3 | 11 223 34 |
| 17 | 0 | 2 | ST 343 432 R |
| 18 | 0 | 3 | 34 343 24 |
+----+------+--------+--------------+
I want to show like this into one query:
Product Columns | *code_keys rows > columns* |
+-----------+------+------+------+--------------+----------+
| productid | da | ig | des | St Code | Rear Les |
+-----------+------+------+------+--------------+----------+
| 5 | 78 | 33 | 23 | ST 102 200 R | 12 000 33|
| 8 | 88 | 13 | 21 | ST 100 101 R | 11 223 34|
+-----------+------+------+------+--------------+----------+
Any ideas?

Answer 1

You can do this using CASE statement:
SELECT p.productid, p.da, p.ig, p.des
,GROUP_CONCAT(CASE WHEN ck.title = 'St Code'
THEN cv.value ELSE NULL END) AS 'St Code'
,GROUP_CONCAT(CASE WHEN ck.title = 'Rear Les'
THEN cv.value ELSE NULL END) AS 'Rear Les'
FROM Products p
JOIN code_values cv ON p.productid = cv.pid
JOIN code_keys ck ON cv.codeid = ck.codeid
GROUP BY p.productid;
If you have unknown number of code_keys you can try this dynamic query:
SET #sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'GROUP_CONCAT(CASE WHEN `title` = ''',
`title`,
''' THEN cv.value ELSE NULL END) AS `',
`title`, '`'
)
) INTO #sql
FROM code_keys ck JOIN code_values cv ON cv.codeid = ck.codeid;
SET #sql = CONCAT('SELECT p.productid, p.da, p.ig, p.des, ', #sql,'
FROM Products p
JOIN code_values cv ON p.productid = cv.pid
JOIN code_keys ck ON cv.codeid = ck.codeid
GROUP BY p.productid
');
PREPARE stmt FROM #sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
Output:
| PRODUCTID | DA | IG | DES | ST CODE | REAR LES |
--------------------------------------------------------
| 5 | 78 | 33 | 23 | ST 102 200 R | 12 000 33 |
| 8 | 88 | 13 | 21 | ST 100 101 R | 11 223 34 |
See this SQLFiddle