Very very slow query. How can I improve it? - php

the following query is used in my Wordpress blog, it gets the categories that a user has posted in. When he has a post in the category, the name of the category is shown.
It is a very very slow query because it is a big database and I have problems with the hosting company.
I have 3 categories, with id 3 called News, 4 called Articles and 5 called Others. My code is:
<?php
$author = get_query_var('author');
$categories = $wpdb->get_results("
SELECT DISTINCT(terms.term_id) as ID, terms.name, terms.slug, tax.description
FROM $wpdb->posts as posts
LEFT JOIN $wpdb->term_relationships as relationships ON posts.ID = relationships.object_ID
LEFT JOIN $wpdb->term_taxonomy as tax ON relationships.term_taxonomy_id = tax.term_taxonomy_id
LEFT JOIN $wpdb->terms as terms ON tax.term_id = terms.term_id
WHERE 1=1 AND (
posts.post_status = 'publish' AND
posts.post_author = '{$post->post_author}' AND
tax.taxonomy = 'category' )
ORDER BY terms.term_id ASC
");
?>
<ul>
<?php foreach($categories as $category) : ?>
<?php if ( ($category->ID == '3') || ($category->ID == '4') || ($category->ID == '5')) { ?>
<li>
<a href="<?php echo get_category_link( $category->ID ); ?>/?author_name=<?php echo $curuser->user_login; ?>" title="<?php echo $category->name ?>">
<?php echo $category->name; ?>
</a>
</li>
<?php } ?>
<?php endforeach; ?>
</ul>
Thank you all!

Judging by the looks of the wordpress database I have lying around, I'm guessing there is no index on the columns you are using in your WHERE clause for the wp_posts table.
Try adding an index like this:
ALTER TABLE wp_posts ADD INDEX (post_author,post_status).
I bet you see a speed up from that.
The best thing to do however is to run that query manually with an EXPLAIN in front of the SELECT, and analyze the output.

Have you indexes on posts.ID, relationships.object_ID, relationships.term_taxonomy_id, tax.term_taxonomy_id, tax.term_id, terms.term_id, posts.post_status, posts.post_author and tax.taxonomy ?

Related

how to show a featured image in wordpress using the $wpdb class

I am trying to get posts from an external website to show on my own website and I am simply achieving this with the wordpress $wpdb class.
I have managed to display the titles of the posts from the external website on to my website however, I am having trouble displaying the featured image that is associated with it's own post.
Any help would be appreciated.
<?php
$mydb = new wpdb('root','','test','localhost');
$rows = $mydb->get_results(" select post_title, guid FROM wp_posts WHERE post_parent = '21' ");
echo '<ul>';
foreach ($rows as $obj) : ?>
<li><?php echo $obj->post_title; ?></li>
<?php echo $obj->meta_value; ?>
<?php
endforeach;
echo '</ul>';
?>
I managed to get the associated featured image for a post from the external database using the following SQL query below:
"SELECT
p1.*,
wm2.meta_value
FROM
wp_posts p1
LEFT JOIN
wp_postmeta wm1
ON (
wm1.post_id = p1.id
AND wm1.meta_value IS NOT NULL
AND wm1.meta_key = '_thumbnail_id'
)
LEFT JOIN
wp_postmeta wm2
ON (
wm1.meta_value = wm2.post_id
AND wm2.meta_key = '_wp_attached_file'
AND wm2.meta_value IS NOT NULL
)
WHERE
p1.post_status= %s
AND p1.post_type=%s
ORDER BY
p1.post_date DESC
LIMIT 4", 'publish','post'));

Php SQL inner join?

So I'm making a portfolio website where I can post and edit blogs.
I'm making the blog edit page and I'm having trouble with combining two table together.
The first table is for the blogs and the second table holds all the different blog categories.
Here's how I'm getting the blog posts:
$qStr = "SELECT post_title, post_content, post_description, post_active, category_id FROM posts WHERE post_id = {$post_id}";
Here's how I'm getting the blog categories:
$qStr = "SELECT category_name FROM categories WHERE category_id = {$category_id}";
So in my edit blog post page I have a dropdown box that I need to show which category that blog post is in, and be able to change it. I have a category_id in my blog table. My question is how do I get the dropdown to show which category the post is under?
Right now my drop down code looks like this (note: Right now I'm just populating the dropdown with all the categories)
<div class="form-group">
<label for="categorySelect" class="col-lg-2 control-label">Category</label>
<div class="col-lg-3">
<select class="form-control" id="categorySelect">
<?php
foreach ($categories as $cat) {
echo("<option>{$cat['category_name']}</option>");
}
?>
</select>
</div>
</div>
You need to set up the selected attribute for select (option) element, something like this:
<?php
foreach ($categories as $cat) {
if ($cat['category_name'] == $category_of_your_post)
echo "<option selected=\"selected\">{$cat['category_name']}</option>";
else
echo "<option>{$cat['category_name']}</option>";
}
?>
BTW, I think that you have the wrong queries (if I understood correctly your question). Basically you need to retrieve the category_id of your post and perform an equality question against the array of categories:
$qStrBlog = "SELECT post_title, post_content, post_description, post_active, category_id FROM posts WHERE post_id = {$post_id}";
$qStrCat = "SELECT category_id, category_name FROM categories";
And then:
<?php
foreach ($categories as $cat) {
if ($cat['category_id'] == $blog_data['category_id'])
echo "<option selected=\"selected\">{$cat['category_name']}</option>";
else
echo "<option>{$cat['category_name']}</option>";
}
?>
You have two options:
Add a selected attribute with an if-condition in the foreach loop:
foreach ($categories as $cat) {
echo '<option';
if ($cat['category_id'] == $post['category_id']) echo ' selected';
echo '>'.$cat['category_name'].'</option>';
}
Or use an INNER JOIN on the post SELECT query:
$qStr = "SELECT p.post_title, p.post_content, p.post_description, p.post_active, p.category_id, c.category_name FROM posts INNER JOIN categories c ON c.category_id = p.category_id WHERE post_id = {$post_id}";
and throw the first option element as the "default currently selected" option:
<select class="form-control" id="categorySelect">
<option value="<?= $post['category_id'] ?>"><?= $post['category_name'] ?> (current)</option>
<?php
foreach ($categories as $cat) {
echo("<option>{$cat['category_name']}</option>");
}
?>
</select>
I've made the assumption that you've correctly loaded your result from the first SELECT query into $post. Note that if it's possible to not set a Category to a Post, you should use LEFT JOIN instead and wrap the first option element output contingent on $post['category_id'] not being empty.

WordPress posts ordered by category and then date

I have no idea how to do this, this is what needs to happen. Posts need to display in this order:
Posts in Category 1 (that's the name, not the ID though I can use
the ID it's 22)
Posts in Category 2 (id is 25)
the rest of the posts
Each of these should be in order from newest to oldest and the ones in the third tier should not include any duplicates from the first two categories.
I tried using a UNION but I could never get the order correct, then found out UNION only supports ONE 'ORDER BY' at the end, which jumbles them all up, defeating the purpose.
Here's the other issue. This has to work with $wp_pagenavi, and the current method just dumps them all out on one page.
Here's what I currently have:
<div id="content" class="post right">
<?php
$query = "(SELECT * FROM $wpdb->posts LEFT JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) WHERE $wpdb->posts.post_status = 'publish' AND $wpdb->term_taxonomy.taxonomy = 'category' AND $wpdb->term_taxonomy.term_id = 22 ORDER BY post_date DESC) UNION ";
$query .= "(SELECT * FROM $wpdb->posts LEFT JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) WHERE $wpdb->posts.post_status = 'publish' AND $wpdb->term_taxonomy.taxonomy = 'category' AND $wpdb->term_taxonomy.term_id = 25 ORDER BY post_date DESC)";
error_log($query);
$pageposts = $wpdb->get_results($query, OBJECT);
?>
<?php if ($pageposts) : ?>
<?php global $post; ?>
<?php foreach ($pageposts as $post) : ?>
<?php setup_postdata($post); ?>
<div class="article">
<p class="post-title"><?php the_title(); ?></p>
<?php the_time('F jS, Y') ?><br />
<?php the_excerpt(); ?>
</div>
<?php if ( $wp_query->max_num_pages > 1 ) : ?>
<div class="navigation">
<?php wp_pagenavi(); ?>
</div>
<?php endif; ?>
<?php endforeach; ?>
<?php else : ?>
<div id="post-0" class="post error404 not-found">
<h1>Not Found</h1>
<div class="entry">
<?php
if ( is_category() ) { // If this is a category archive
printf("<p>Sorry, but there aren't any posts in the %s category yet.</p>", single_cat_title('',false));
} else if ( is_date() ) { // If this is a date archive
echo("<p>Sorry, but there aren't any posts with this date.</p>");
} else if ( is_author() ) { // If this is a category archive
$userdata = get_userdatabylogin(get_query_var('author_name'));
printf("<p>Sorry, but there aren't any posts by %s yet.</p>", $userdata->display_name);
} else if ( is_search() ) {
echo("<p>No posts found. Try a different search?</p>");
} else {
echo("<p>No posts found.</p>");
}
?>
<?php get_search_form(); ?>
</div>
</div>
From your question it sounds like you want all the published posts, not just the ones in the categories you mentioned.
Therefore, you need WHERE criteria to select them all. I don't think you want a UNION of the ones in just in those categories.
If you use an ORDER BY clause like this, you should get them in the order you're mentioning.
ORDER BY $wpdb->term_taxonomy.term_id = 22 DESC,
$wpdb->term_taxonomy.term_id = 25 DESC,
$wpdb->posts.post_date DESC
The first two terms evaluate to either true 1 or false 0. Ordering them DESC puts the trues first. The last term puts everything in descending order of data.

Wordpress - Order by author if different than "admin"

In "category.php" file I need to order my posts in this strange way:
First all the posts where author is different than "admin" (in alphabetical order by title)
Than all the post by "admin" (in the same alphabetical order)
Here is the standard code I use to do my query:
<?php global
$wp_query;
query_posts(
array_merge(
array('orderby' => 'title', 'order' => 'ASC'),
$wp_query->query
)
);
?>
Any idea about how to accomplish it without nesting two queries?
Thanks in advance!
EDIT: Following is some code that was tried, as suggested by Sepster in a previous version of his answer. But at the moment this code starts showing all the posts from 'admin' (instead of the others) until the posts with author different than 'admin' come. At that point it breaks the results and jump to the next page of results.
<?php
global $wp_query;
query_posts(
array_merge(
array('orderby' => 'title', 'order' => 'ASC'),
$wp_query->query
)
);
$adminPosts = false;
for ($i=1; $i<=2; $i++) {
while ( $wp_query->have_posts() ) {
$wp_query->the_post();
$author = get_the_author();
if ($author == 'admin' && $adminPosts == false) break;
if ($author != 'admin' && $adminPosts == true) break;
// ALL MY STUFF
} // end while
rewind_posts();
$adminPosts=true;
} // end FOR
?>
Update:
I've finally come up with a somewhat workable solution for this, but it's fair to say this really is an excercise in academics; Yes, it's do-able without executing a second loop, but really, it's pretty convoluted.
The solution is, in summary
Develop a custom SQL statement that will return the rows in the order required.
This is because in SQL, the only way to get the results in the order you need is by doing a UNION of your two subsets. To my knowledge there's no way of doing that using the "normal" WP query operations.
Execute this query, and loop over its results rather than a standard "the loop".
This is because we're getting back a recordset, rather than a WP_Query object.
Set the "Blog pages show at most X posts" setting to 1.
(on /wp-admin/options-reading.php)
A common complaint is pagination breaking when using custom queries (incidentally, the query_posts() method you're using is susceptible to this issue).
There are numerous turorials on how to do this properly, eg:
https://codex.wordpress.org/Making_Custom_Queries_using_Offset_and_Pagination
https://codex.wordpress.org/Pagination#Troubleshooting_Broken_Pagination
The first of those recommends the implementation of "Offset and Manual Pagination".
The closest I've found to an implementation of this in conjunction with a custom SQL statement is this https://wordpress.stackexchange.com/a/28717. I've borrowed heavily from this answer (and so I recommend you go over and give it an up-vote!).
However, this technique (among other more "standard" custom query approaches) suffers from a known behaviour where WP produces a 404 on the final page (if I understand correctly, because WP is still using its own query and associated max-page=posts-per-page/posts calculations to map between the page number in the URL and the delivered content).
Refer http://wordpress.org/support/topic/explanation-and-workaround-for-error-404-on-category-pagination?replies=14 for details about this issue, and a proposed solution (which unfortunately won't work for our custom SQL approach).
A known "work-around" for this issue is to reduce the number of posts-per-page to 1, as per eg http://wordpress.org/support/topic/custom-post-type-pagination-404-on-last-page
So, assuming you're happy with a global setting of 1 posts-per-page (remember you'd need to override this manually in your custom queries), here's the code:
functions.php:
...
function get_users_posts_last($userDisplayName = 'Admin', $categoryName = '') {
global $wpdb, $paged, $max_num_pages;
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
$post_per_page = 5;
$offset = ($paged - 1)*$post_per_page;
$sql = "
SELECT SQL_CALC_FOUND_ROWS q.* FROM
(
(
SELECT
p.*
FROM
{$wpdb->posts} p
INNER JOIN {$wpdb->users} u ON p.post_author = u.ID
LEFT JOIN {$wpdb->term_relationships} tr ON p.ID = tr.object_id
LEFT JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
LEFT JOIN {$wpdb->terms} t ON tt.term_id = t.term_id
WHERE
tt.taxonomy = 'category'
AND p.post_status = 'publish'
AND p.post_type = 'post'
AND u.display_name != '{$userDisplayName}'
" . ( $categoryName != '' ? "AND t.name = '{$categoryName}'" : "" ) . "
ORDER BY
p.post_title ASC
)
UNION
(
SELECT
p.*
FROM
{$wpdb->posts} p
INNER JOIN {$wpdb->users} u ON p.post_author = u.ID
LEFT JOIN {$wpdb->term_relationships} tr ON p.ID = tr.object_id
LEFT JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
LEFT JOIN {$wpdb->terms} t ON tt.term_id = t.term_id
WHERE
tt.taxonomy = 'category'
AND p.post_status = 'publish'
AND p.post_type = 'post'
AND u.display_name = '{$userDisplayName}'
" . ( $categoryName != '' ? "AND t.name = '{$categoryName}'" : "" ) . "
ORDER BY
p.post_title ASC
)
) q
LIMIT {$offset}, {$post_per_page};
";
$sql_result = $wpdb->get_results( $sql, OBJECT);
$sql_posts_total = $wpdb->get_var( "SELECT FOUND_ROWS();" );
$max_num_pages = ceil($sql_posts_total / $post_per_page);
return $sql_result;
}
...
category.php:
...
$postList = get_users_posts_last('admin'); // Note you can also pass a category name if necessary
if($postList) {
global $post;
foreach( $postList as $key=>$post ) {
setup_postdata($post);
// Render the post here
?>
<header class='entry-header'><h1 class='entry-title'><?php the_title(); ?></h1></header>
<div class='entry-content'><?php the_content(); ?></div>
<?php
}
// Render pagination here
?>
<div class="navigation">
<div class="previous panel"><?php previous_posts_link('« Previous page',$max_num_pages) ?></div>
<div class="next panel"><?php next_posts_link('Next page »',$max_num_pages) ?></div>
</div>
<?php
}
...
Or, just set up two separate queries ;-)

how to eliminate a particular category from query

I have been presented with this code. The code displays the title headings of the latest 10 WordPress posts from the database. What I need to do is to eliminate a particular category from this. Can anyone help?
<?php require_once 'news/wp-config.php';
$howMany = 0;
$query ="SELECT `ID`, `post_title`,'post_category', `guid`,SUBSTRING_INDEX(`post_content`, ' ', 100) AS `post_excerpt` FROM $wpdb->posts WHERE `post_status`= \"publish\" AND `post_type` = \"post\" ";
$posts = $wpdb->get_results($query);
$posts = array_reverse($posts);
foreach($posts as $post)
{
if($howmany<10)
{
$link = $post->guid;
echo "<li><a target='_blank' href='$link'>$post->post_title</a></li>";
$howmany++;
}
}
?>
Or, you could use a second loop, something like this :
<div>
<h3>Fresh Posts</h3>
<ul>
<?php
$my_query = new WP_Query("cat=-3&order=DESC&posts_per_page=10");
echo "<pre>"; print_r($my_query->query_vars); echo "</pre>"; // shows the variables used to parse the query
echo "<code style='width: 175px;'>"; print_r($my_query->request); echo "</code>"; // shows the parsed query
while ($my_query->have_posts()) : $my_query->the_post(); //standard loop stuff
$do_not_duplicate[] = $post->ID;?>
<li id="post-<?php the_ID(); ?>"><?php the_title(); ?></li>
<?php endwhile; ?>
</ul>
</div>
once again WP 2.8.x. Lots of good info here : WordPress loop documentation
Determine the category you don't need and add an extra AND to your WHERE clause:
AND post_category != 3
You can do it either of 2 places. The most efficient is to do it in the query:
$query ="SELECT ID, post_title, post_category, guid, SUBSTRING_INDEX(post_content, ' ', 100) AS `post_excerpt`
FROM $wpdb->posts
WHERE post_status= 'publish'
AND post_type = 'post'
AND post_category!= 'unwanted string' ";
The other place to do it, if for some reason you need all the results, but you want to use the unwanted category somewhere else, is when you retrieve the results:
if($howmany<10 && post['post_category']!='unwanted string') {
'Noticeboard' is the name of the category i want to eliminate. but if i write that, it dispalys a parse error.
Because you must insert the category ID in the query, not the category name.
To get that, just watch in the database wp_categories table.
Some links about wordpress database:
http://blog.kapish.co.in/2008/01/18/wordpress-database-schema/
http://wpbits.wordpress.com/2007/08/08/a-look-inside-the-wordpress-database/
Anyway, I think it's more hard than this. Look at post2cat table.
So, you have to do a subquery.
I am not sure which WP version you are using, so this 'answer' has a few caveats.
Caveat 1 : This is not a complete answer, more like a pointer
Caveat 2 : The query below works with WP 2.8.x so YMMV
The query below shows how to link posts back to their categories. You can use the NOT IN mySQL operator to exclude the category you do not want by its ID
SELECT
wp_posts.*
FROM
wp_posts
INNER JOIN
wp_term_relationships
ON
(wp_posts.ID = wp_term_relationships.object_id)
INNER JOIN
wp_term_taxonomy
ON
(wp_term_relationships.term_taxonomy_id = wp_term_taxonomy.term_taxonomy_id)
WHERE
wp_term_taxonomy.taxonomy = 'category'
AND
wp_term_taxonomy.term_id NOT IN ('3')
AND
wp_posts.post_type = 'post'
AND
(wp_posts.post_status = 'publish' OR wp_posts.post_status = 'future')
GROUP BY
wp_posts.ID
ORDER BY
wp_posts.post_date
DESC
The line breaks and indenting are idiosyncratic, but (hopefully) make it easier for you to see what is going on with this query.
I hope this helps.

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