MySQL pivot row to column dynamically - mysql

Question

i have table:day
id | jour
1 Lundi 01 Août 2016
2 Mardi 02 Août 2016
3 Mercredi 03 Août 2016
4 Jeudi 04 Août 2016
there will be 50 rows i want output like:
Lundi 01 Août 2016 Mardi 02 Août 2016 Mercredi 03 Août 2016
1 2 3

Answer 1

you can do it easy with this queries: first generate the query and then execute it as prepared statement.
SET SESSION group_concat_max_len = 1000000;
SELECT
CONCAT('SELECT ',
GROUP_CONCAT(
CONCAT (
"MAX(IF(`jour` = '",jour,'\',id,NULL)) AS `',jour,'`'
)
),
' FROM `day`'
) INTO #SQL
FROM
( SELECT *
FROM `day`
ORDER BY id
LIMIT 1,2
) AS data;
select #SQL; -- see the query only for debug
PREPARE stmt FROM #SQL;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
sample
MariaDB [yourSchema]> select * from day;
+----+------------------------+
| id | jour |
+----+------------------------+
| 1 | Lundi 01 Août 2016 |
| 2 | Mardi 02 Août 2016 |
| 3 | Mercredi 03 Août 2016 |
| 4 | Jeudi 04 Août 2016 |
+----+------------------------+
4 rows in set (0.00 sec)
MariaDB [yourSchema]> SELECT
-> CONCAT('SELECT ',
-> GROUP_CONCAT(
-> CONCAT (
-> "MAX(IF(`jour` = '",jour,'\',id,NULL)) AS `',jour,'`'
-> )
-> ),
-> ' FROM `day`'
-> ) INTO #SQL
-> FROM `day`;
Query OK, 1 row affected (0.00 sec)
MariaDB [yourSchema]> PREPARE stmt FROM #SQL;
Query OK, 0 rows affected (0.00 sec)
Statement prepared
MariaDB [yourSchema]> EXECUTE stmt;
+---------------------+---------------------+------------------------+---------------------+
| Lundi 01 Août 2016 | Mardi 02 Août 2016 | Mercredi 03 Août 2016 | Jeudi 04 Août 2016 |
+---------------------+---------------------+------------------------+---------------------+
| 1 | 2 | 3 | 4 |
+---------------------+---------------------+------------------------+---------------------+
1 row in set (0.00 sec)
MariaDB [yourSchema]> DEALLOCATE PREPARE stmt;
Query OK, 0 rows affected (0.00 sec)
MariaDB [yourSchema]>