sql - MySql select dynamic row values as column names

Question

This is my given table:

+---------+------------+-------------------+--------------------------+---------------+---------------+
| exec_id | project_id | flow_id           | job_id                   | start_time    | end_time      |
+---------+------------+-------------------+--------------------------+---------------+---------------+
|   10919 |         16 | my_flow_cleanup   | init                     | 1408480308611 | 1408480308686 |
|   10919 |         16 | my_flow_cleanup   | job_id_1                 | 1408480309212 | 1408480309426 |
|   10919 |         16 | my_flow_cleanup   | job_id_2                 | 1408480308721 | 1408480308776 |
|   10919 |         16 | my_flow_cleanup   | job_id_3                 | 1408480308827 | 1408480309171 |
+---------+------------+-------------------+--------------------------+---------------+---------------+

And I want to achieve a select like this:

exec_id     init_start            init_end            job_id_1_start       job_id_1_end       job_id_2_start        job_id_2_end        job_id_3_start      job_id_3_end
10919       1408480308611         1408480308686       1408480309212        1408480309426      1408480308721         1408480308776       1408480308827       1408480309171

I have spent more than 2 days on this, with very little success. This question helped me, but not completely. As you can see, the other question deals with taking 2 columns and converting them to 2 rows. But I have to take 3 columns and convert them into 2 rows.

Can anyone help me with this? Is it even possible in MySQL?

EDIT 1

Thanks Khalid Junaid for the answer, it solved my problem. I have to make one more modification. I have to order the selected columns by start_time in the ascending order.

E.g.:

+---------+------------+-------------------+----------+---------------+---------------+
| exec_id | project_id | flow_id           | job_id   | start_time    | end_time      |
+---------+------------+-------------------+----------+---------------+---------------+
|   10919 |         16 | my_flow_cleanup   | init     | 10            | 15            |
|   10919 |         16 | my_flow_cleanup   | job_id_1 | 30            | 40            |
|   10919 |         16 | my_flow_cleanup   | job_id_2 | 40            | 50            |
|   10919 |         16 | my_flow_cleanup   | job_id_3 | 20            | 25            |
+---------+------------+-------------------+----------+---------------+---------------+

Current query will return:

exec_id     init_start            init_end            job_id_1_start       job_id_1_end       job_id_2_start        job_id_2_end        job_id_3_start      job_id_3_end
10919       10                    15                  30                   40                 40                    50                  20                  25

I need:

exec_id     init_start            init_end            job_id_3_start       job_id_3_end       job_id_1_start        job_id_1_end        job_id_2_start      job_id_2_end
10919       10                    15                  20                   25                 30                    40                  40                  50

Please notice that the order of columns is now changed, according to start_time.

I tried to do this with temporary tables and views, I thought it would be very easy. Unfortunately, I don't have create table/create view permissions. Is there a way to achieve this without temp table and views?

Answer 1

As from reference question's approach of using group_concat you can do so,but note one thing as your job ids increases per exec_id group then group_concat approach will not be optimal due to its default length of 1024 characters to concatenate and for your dynamic columns this will surely cross that limit,but this limit can be increased as mentioned in documentation

SET @sql = NULL;

SELECT GROUP_CONCAT(DISTINCT
  CONCAT('MAX(CASE WHEN job_id = ''',
         job_id, 
         ''' THEN start_time END) `',
         job_id,
         '_start`',
         ',',
         'MAX(CASE WHEN job_id = ''',
         job_id,
         ''' THEN end_time END) `',
         job_id,
         '_end`' 
         )

 )
  INTO @sql
  FROM t;

SET @sql = CONCAT('SELECT exec_id, ', @sql, ' 
                     FROM t 
                    GROUP BY exec_id');

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

Fiddle Demo