On the home page of my website I want to display the latest posts to the forum however I don't want to show the same topic twice. How can I modify the code below to do this?
http://punbb.informer.com/wiki/punbb13/integration#recent_10_posts
Basically show the latest posts, but only once for each forum topic/thread.
Add a condition to keep only records where the post is the last post in the topic:
WHERE p.id = (
SELECT pp.id
FROM posts AS pp
WHERE pp.topic_id = t.id ORDER BY pp.posted DESC LIMIT 1
)
If you want only one value per topic, you could group by topic, and from each topic select the most recent post. Then, you could choose the top 10 topics.
I'll write it in SQL, and you can translate that to PHP:
SELECT p.id, p.message, o.subject
FROM
((SELECT t.id
FROM posts AS p LEFT JOIN topics AS t ON p.topic_id = t.id
GROUP BY t.id
HAVING p.posted = MAX(p.posted) ) ids LEFT JOIN topics AS t ON ids.id = t.id) o
LEFT JOIN posts AS p ON o.id = posts.topic_id
ORDER BY p.posted DESC
LIMIT '0,10'
change this line
'SELECT' => 'p.id, p.message, t.subject',
to
'SELECT DISTINCT' => 'p.id, p.message, t.subject',
Related
i am trying to get all topics based on a forum ID.
Those topics need to be ordered by sticky first and then by last post date secondly.
I have this query, working almost fine but it doesn't order the topics in the way i want.
SELECT
forum_posts.posted_by,
forum_posts.posted,
forum_topics.id,
forum_topics.subject,
forum_topics.sticky,
forum_topics.closed
FROM
forum_posts
LEFT JOIN
forum_topics
ON
forum_topics.id=forum_posts.topic_id
WHERE forum_topics.forum_id=$forumdata->id
GROUP BY forum_topics.id
ORDER BY forum_posts.posted DESC
If I read your question correctly, then you only need to make a slight change to the ORDER BY clause:
ORDER BY
forum_topics.sticky, -- just add this
forum_posts.posted DESC;
However, as you are selecting non aggregate columns, my hunch is that you should really be using a subquery to figure out the latest post:
SELECT
ft.*, fp1.*
FROM forum_posts fp1
INNER JOIN
(
SELECT topic_id, MAX(posted) AS max_posted
FROM forum_posts
GROUP BY topic_id
) fp2
ON fp1.topic_id = fp2.topic_id AND
fp1.posted = fp2.max_posted
LEFT JOIN forum_topics ft
ON fp1.id = ft.topic_id
ORDER BY
ft.sticky;
if you need sticky first an then post then you need order by orum_topics.sticky, forum_posts.posted eg:
SELECT
forum_posts.posted_by,
forum_posts.posted,
forum_topics.id,
forum_topics.subject,
forum_topics.sticky,
forum_topics.closed
FROM
forum_posts
LEFT JOIN
forum_topics
ON
forum_topics.id=forum_posts.topic_id
WHERE forum_topics.forum_id=$forumdata->id
GROUP BY forum_topics.id
ORDER BY forum_topics.sticky DESC, forum_posts.posted DESC
I am listing the tags/categories on the user's page. I would like to show the number of posts the user made for each tag. The tags, the posts, and the post-tags are in different tables.
The difficulty is, that there are two kind of posts. The posts, and the comments. They are in the same table, but different type. "question" and "answer". the related_id at the answers are the id of the posts they are related to.
I tried to solve in pretty lot of way but couldn't get it to work.
My db structures:
For tags:
tagid tag_name
For posts
id type(enum:"question","answer") related_id user_id
For post-tags:
post_id tag_id
The code what I tried is the following:
$user_active_query = mysql_query("select p.id,
p.user_id,
pt.post_id,
count(pt.post_id),
pt.tag_id,
t.tagid,
t.tag_name
from posts p
inner join post_tags pt
inner join tags t
on p.id = pt.post_id
and pt.tag_id = t.tagid
where p.user_id = '$uid'
group by t.tagid");
while($useractive = mysql_fetch_array($user_active_query)) {
$user_active_counter = $useractive['count(pt.post_id)'];
echo "<a href='' class='btn btn-mini' style='margin:3px;'>".$useractive['tag_name']." (".$user_active_counter.")</a>";
}
User id is given on the page. "$uid". I am just tired of the lot of try and asking for correction. First it seemed to be the best way to store the post-tags but now this is a nightmare. I mean, for me, its seems impossible to do this with this structure.
You can get both counts i.e the no of answers and no of questions posted by a user ,here is the trick also use proper join syntax you are missing the on clause for join
SELECT
p.id,
p.user_id,
pt.post_id,
COUNT(pt.post_id) all_posts,
COALESCE(SUM(`type` = 'question')) questions,
COALESCE(SUM(`type` = 'answer')) answers,
pt.tag_id,
t.tagid,
t.tag_name
FROM tags t
LEFT JOIN post_tags pt ON(pt.tag_id = t.tagid)
LEFT JOIN posts p ON p.id = pt.post_id
WHERE p.user_id = '$uid'
GROUP BY t.tagid
Note in mysql sum with some expression will result in a boolean
Edit from comments add another condition using OR in your last join so first condition will join the posts that are associated with tags ,and as your explanation tags are not directly linked with answers but answer are linked to their question with related id so can join the related id of each answer to tag id so this way can get the tags for answers too
SELECT
p.id,
p.user_id,
pt.post_id,
COUNT(pt.post_id) all_posts,
COALESCE(SUM(`type` = 'question')) questions,
COALESCE(SUM(`type` = 'answer')) answers,
pt.tag_id,
t.tagid,
t.tag_name
FROM tags t
LEFT JOIN post_tags pt ON(pt.tag_id = t.tagid)
LEFT JOIN posts p ON (p.id = pt.post_id OR p.related_id = pt.post_id)
WHERE p.user_id = '$uid'
GROUP BY t.tagid
I think you only need to include p.type in your group by clause
$user_active_query = mysql_query("
select
p.id,
p.user_id,
pt.post_id,
count(pt.post_id),
pt.tag_id,
t.tagid,
t.tag_name
from posts p
inner join post_tags pt
inner join tags t
on p.id = pt.post_id
and pt.tag_id = t.tagid
where p.user_id = '$uid'
group by t.tagid, p.type"
);
so, we will group per type too.
I'm not sure I fully understand your schema design. But it sounds like you have two join "paths", one to get to the question type posts, and another to get to child answer type posts.
To get the count of the question-type posts (by a specific user) related to each tag, looks like what you have so far, basically:
SELECT t.tagid
, t.tag_name
, COUNT(p.id) AS count_question
FROM tags t
JOIN post_tags pt
ON pt.tag_id = t.tagid
JOIN posts p
ON p.id = pt.post_id
AND p.type = 'question'
WHERE p.user_id = '$uid'
GROUP BY t.tagid
To get the count of the answer-type posts (by a specific user) related to a question related to each tag, we first need to join to the 'question' (to get the tags), and then join to the related answer. This is nearly identical to the first query, except that we add another join to posts table to get the "child" answer-type posts (so we can get a count of the answer-type posts), and we are not restricting the question-type posts to those from the specific user... we are going to count the answer-type posts from a user posted against any user's question.
SELECT t.tagid
, t.tag_name
, COUNT(a.id) AS count_answer
FROM tags t
JOIN post_tags pt
ON pt.tag_id = t.tagid
JOIN posts p
ON p.id = pt.post_id
AND p.type = 'question'
JOIN posts a
ON a.related_id = p.id
AND a.type = 'answer'
WHERE a.user_id = '$uid'
GROUP BY t.tagid
If each of those queries returns a portion of the total count you want to return, those can be combined, but it gets a little bit messy.
The most straightforward approach is to combine those two results with a UNION ALL set operator, and then use that as an inline view, i.e. run another query against the combined resultset.
For example:
SELECT r.tagid
, r.tagname
, SUM(r.count_post) AS count_total
, SUM(IF(r.type='q',r.count_post,0)) AS count_question
, SUM(IF(r.type='a',r.count_post,0)) AS count_answer
FROM (
SELECT 'q' AS type
, t.tagid
, t.tag_name
, COUNT(p.id) AS count_post
FROM tags t
JOIN post_tags pt
ON pt.tag_id = t.tagid
JOIN posts p
ON p.id = pt.post_id
AND p.type = 'question'
WHERE p.user_id = '$uid'
GROUP BY t.tagid
UNION ALL
SELECT 'a' AS type
, t.tagid
, t.tag_name
, COUNT(a.id) AS count_post
FROM tags t
JOIN post_tags pt
ON pt.tag_id = t.tagid
JOIN posts p
ON p.id = pt.post_id
AND p.type = 'question'
JOIN posts a
ON a.related_id = p.id
AND a.type = 'answer'
WHERE a.user_id = '$uid'
GROUP BY t.tagid
) r
GROUP BY r.tag_id
If you aren't interested in the individual counts (of question and answer type posts), then just remove those two expressions from the SELECT list of the outer query, and you can also remove the type='q', type='a' discriminator column from the inline view query.
This isn't the only way to combine the results, but I think it's the easiest way to verify we're getting a "correct" result (we can run just the inline view query and verify that the results from that are correct.
Another approach to combining them is messier, and more difficult to decipher.
We basically need to join to question-type posts from all users, and then do an outer join operation to the answer-type posts from the specific user.
We can use predicates in the WHERE clause to filter out the rows, so that return only rows that have a matching answer-type row -OR- are a question-type row poseted by the specified user.
In the SELECT list, we need to do some additional filtering, so that we filter out posts from other users.
Something like this:
SELECT t.tagid
, t.tag_name
, COUNT(DISTINCT IF(p.user_id='$uid',p.id,NULL))
+ COUNT(DISTINCT a.id) AS count_total
, COUNT(DISTINCT IF(p.user_id='$uid',p.id,NULL)) AS count_question
, COUNT(DISTINCT a.id) AS count_question
FROM tags t
JOIN post_tags pt
ON pt.tag_id = t.tagid
JOIN posts p
ON p.id = pt.post_id
AND p.type = 'question'
LEFT
JOIN posts a
ON a.related_id = p.id
AND a.type = 'answer'
AND a.user_id = '$uid'
WHERE p.user_id = '$uid'
OR a.id IS NOT NULL
GROUP BY t.tagid
But, I'd don't really like this query, it's too hard to figure out what's going on. I'd opt for the (previous) query, with the UNION ALL inline view. That's easier to decipher.
I'm trying to get count of posts
in "posts" table,
i have id,topic_id (topic_id= the topic id)
in "topics" table,
i have id,f_id (f_id= the forum id )
i try while and while, but not wor
how can i count the posts?
for ex:
<php?
$test2=mysql_query("SELECT *, COUNT(topic_id) AS post_count FROM posts t LEFT JOIN topics p ON p.id = t.id WHERE `f_id`='1' GROUP BY t.id") or die (mysql_error());
?>
Try this query :
SELECT *, COUNT(topic_id) AS post_count
FROM posts t
LEFT JOIN topics p
ON p.id = t.id AND `f_id`='1'
GROUP BY t.id
I have two tables :
posts : id,title,content,show,created_at
comments: id,post_id,created_at
I'm trying to order posts by most commented.
SELECT *, COUNT(comments.id) AS total_comments
FROM comments LEFT JOIN posts ON posts.id = comments.post_id
WHERE posts.show = '1'
GROUP BY complains.id
ORDER BY total_comments DESC
The problem is that the posts with 0 comments don't appear.
Any help would be much appreciated.
With your join above, you are incorrectly joining to get commens that have posts
You should have done a right join or swap the tables in left join like below.
Select *, COUNT(comments.id) as total_comments
FROM posts
LEFT outer JOIN comments on posts.id = comments.post_id
WHERE posts.show = '1'
GROUP BY posts.id
ORDER BY total_comments DESC
You need to do a RIGHT JOIN instead of a LEFT JOIN. Or swap the tables in the LEFT JOIN clause.
While there are many ways to solve this, I think this code is easy to read and understand.
The query in the LEFT JOIN can be copied out and run on its own to help debug. Then you join that result set to the posts table and order the results.
SELECT p.*, IFNULL(c.total_comments, 0) as total_comments
FROM posts p
LEFT JOIN (select post_id, count(post_id) as total_comments from comments group by post_id) as c ON p.id = c.post_id
WHERE p.show = '1'
ORDER BY c.total_comments DESC
im running a query that usses 3 tabels "post, likes and comment" i need to get the ammount of likes and comments the post has got, and at the same time get the basic info from the post table so im using the query bellow but the problem is that it copys the value likeAmount to commentAmount if likes is bigger unless comments is 0.
SELECT post.*, COUNT(likes.id) as 'LikeAmount', COUNT(comment.id) as 'commentAmount' FROM post
LEFT JOIN likes ON post.id = likes.post
LEFT JOIN comment ON post.id = comment.post
GROUP BY post.id
ORDER BY LikeAmount DESC"
so that doesnt work but when i add distinct it does work, so when its like this:.
SELECT post.*, COUNT(distinct likes.id) as 'LikeAmount', COUNT(distinct comment.id) as 'commentAmount' FROM post
LEFT JOIN likes ON post.id = likes.post
LEFT JOIN comment ON post.id = comment.post
GROUP BY post.id
ORDER BY LikeAmount DESC";
i dont see why it works with distinct and doesnt with out, and does distinct mather performance wise or does it make no diffrence sinds it will be used in a website that has a lott of trafic..
try this, not short, but readable:
SELECT
p.*,
pl.like_count,
pc.comment_count
FROM post p
#join likes
LEFT OUTER JOIN (
SELECT
post,
COUNT(*) AS like_count
FROM likes
GROUP BY post
) AS pl
ON pl.post = p.id
#join comments
LEFT OUTER JOIN (
SELECT
post,
COUNT(*) AS comment_count
FROM comment
GROUP BY post
) AS pc
ON pc.post = p.id
Perhaps using SUM instead of COUNT to handle the records where there is no join would work, and should perform just as fast:
SELECT post.id,
SUM(IF(likes.id IS NULL,0,1)) as 'LikeAmount',
SUM(IF(comment.id IS NULL,0,1)) as 'commentAmount'
FROM post
LEFT JOIN likes ON post.id = likes.post
LEFT JOIN comment ON post.id = comment.post
GROUP BY post.id
ORDER BY LikeAmount DESC"