Highest Status per ID per category - mysql

Question

I'm struggling with an problem to make a query of the following:
I have an table called Article_Statuses (and the main table Articles, with ArticleID as p.key) and has the following structure
ID, ArticleID, Status, Status_Date, Category
In this table I collect all the statuses of the articles (ArticleID) per category (which are predefined), the highest ID per category is the latest status of that category, herewith some data:
1, BB0001, LFS, 15-01-2015, LIC
2, BB0001, LFA, 19-01-2015, LIC
3, BB0001, SA, 10-01-2015, FIS
4, BB0001, CA, 19-01-2015, FIS
5, BB0002, LFS, 10-01-2015, LIC
6, BB0002, LFA, 11-01-2015, LIC
7, BB0003, CA, 19-01-2015, FIS
I want to make a query with the following result:
ArticleID, Status LIC, Status_Date LIC, Status FIS, Status_Date FIS
BB0001, LFA, 19-01-2015, CA, 19-01-2015
BB0002, LFA, 11-01-2015, ,
BB0003, , , CA, 19-01-2015
I found the following solution which works for only one category, I'm stuck with adding the other categories...
SELECT `a`.`ArticleID`, `b`.`Status_Date` AS `LIC_Date`, `b`.`Status` AS `LIC_Status`
FROM `Articles` `a`
INNER JOIN `Article_Statuses` `b` ON `a`.`ArticleID` = `b`.`ArticleID`
INNER JOIN ( SELECT `ArticleID`, MAX( `ID` ) `MAXID`
FROM `Article_Statuses`
WHERE `Category` = 'LIC' GROUP BY `ArticleID` ) `c`
ON `b`.`ArticleID` = `c`.`ArticleID` AND `b`.`ID` = `c`.`MAXID`
WHERE `a`.`Partner` = 10
GROUP BY `a`.`ArticleID`
ORDER BY `a`.`ArticleID` ASC

Answer 1

What is the meaning of "Partner" in your query? You didn't mentioned it anywhere earlier so I'm guessing it's not important.
How many different categories do you have? Just two or more? I'm asking because returning data in such a way is far for being fast and optimal.
It would be something like:
SELECT
a.ArticleID,
b.Status_Date AS LIC_Date, b.Status AS LIC_Status,
d.Status_Date AS FIS_Date, d.Status AS FIS_Status
FROM Articles AS a
INNER JOIN Article_Statuses AS b ON a.ArticleID = b.ArticleID
INNER JOIN (
SELECT ArticleID, MAX( ID ) AS ID
FROM Article_Statuses
WHERE Category = 'LIC' GROUP BY ArticleID
) AS c ON b.ArticleID = c.ArticleID AND b.ID = c.ID
INNER JOIN Article_Statuses AS d ON a.ArticleID = d.ArticleID
INNER JOIN (
SELECT ArticleID, MAX( ID ) AS ID
FROM Article_Statuses
WHERE Category = 'FIS' GROUP BY ArticleID
) AS e ON d.ArticleID = e.ArticleID AND d.ID = e.ID
WHERE a.Partner = 10
ORDER BY a.ArticleID ASC
Basically you repeat joins just with different aliased - I used "d" and "e" but it's better to use something meaningful like "LIC_category" instead of just "b".
You also should use left join instead of inner join if some categories can be empty as in your example.

Answer 2

This is the query which returns desired result:
select a.articleid,
b.status_date as LIC_Date, b.status as LIC_Status,
c.status_date as FIS_Date, c.status as FIS_Status
from Articles a
left join Article_Statuses b on b.ArticleID =a.articleid and
b.id = (select max(id) from Article_Statuses ast
where ast.articleid=a.articleid and ast.category='LIC')
left join Article_Statuses c on c.ArticleID =a.articleid and
c.id = (select max(id) from Article_Statuses ast
where ast.articleid=c.articleid and ast.category='FIS')
order by a.articleid
I used left joins because not for every article both categories are present.