[mysql][php] Problematic join results from two tables and filtering in php

Question

I am looking for a way to get data about the production process. I have two tables:

production: stores product information

timeline: there are details of the employee and when he made the production step

production:

--------------------------
internal | type of closing
--------------------------
123      | close
122      | open

timeline:
------------------------------------------------
id | internal | employee | date        | step
------------------------------------------------
1  | 123      | E01      | 2017-11-11  | diag
2  | 123      | E03      | 2017-11-12  | rep
3  | 122      | E06      | 2017-11-05  | diag

Steps from the column steps are predetermined (diag,rep,test)

I would like to get a result:

----------------------------------------------------------------------------------------
internal | diag | date_diag  | rep  | date_rep   | test  | date_test  | type of closing
----------------------------------------------------------------------------------------
123      | E01  | 2017-11-11 | E03  | 2017-11-12 | NULL  | NULL       | close
122      | E06  | 2017-11-05 | NULL | NULL       | NULL  | NULL       | open

To filter this result later by date_rep(or)date_test(or)date_diag and type of closing (close/open). How can this be done using Mysql and PHP? With the best performance, because the base is huge.

Answer 1

You should use different aliases on the same table, joining the table in a way like this:

SELECT T1.internal, 
       T1.employee, 
       T1.date as date_diag,
       T2.employee as rep,
       T2.date as date_rep,
       NULL,
       NULL,
       P.description
FROM timeline T1
INNER JOIN production P ON T1.internal = P.internal 
LEFT JOIN timeline T2 ON T1.internal = T1.internal and T2.step = 'rep'
WHERE T1.step ='diag'

This is a starting point close enough to the solution.