Question

I have a blog SQL system with ‘posts’ table like this (id, theme, title, content, created).

I would like to get the last 3 titles of each post theme, to display in a table, but I didn’t get it.

I tried this SQL code:

SELECT *
FROM posts
GROUP BY theme
ORDER BY created DESC
LIMIT 0,3

But this gives me the last 3 posts of the table!!!

Can you please help me?

Thanks in advance.

Answer 1

Josvic Zammit’s answer is in parts right (+1 from me) but you don’t have to perform the query per theme. This is a way you can do it in MySQL, although it would surely be easier to “perform the query per theme” in PHP or whatever.

SELECT * FROM
(
SELECT
IF(@prev != sq.theme, @rownum:=1, @rownum:=@rownum + 1) AS rownumber, @prev:=sq.theme, sq.*
FROM
(
    SELECT
    *
    FROM
    posts
    , (SELECT @rownum:=0, @prev:=0) r 
    ORDER BY theme, created DESC
) sq
) q
WHERE q.rownumber <= 3

Note that I unfortunately can’t test it right now, but it should work. Also note, that this query might be slower than performing a simpler query per theme.