通过SQL检索带有特色图像的wordpress帖子

Question

I'm using this query in a PHP script outside Wordpress to retrieve entries with their featured images

SELECT  ( SELECT guid FROM wp_posts WHERE id = m.meta_value ) AS url 
FROM wp_posts p, wp_postmeta m
WHERE p.post_type =  'post'
AND p.post_status =  'publish'
AND p.id = m.post_id
AND m.meta_key =  '_thumbnail_id'

...and it works fine.

But this way I get full-size image URL. I need to retrieve 'medium' or 'thumbnail' sizes of these images.

¿Any way to achieve this?

Answer 1

here is the response :

SELECT TITRE,DESCR,URL, CONCAT(LEFT(IMG, LENGTH(IMG) - LOCATE('.', 
REVERSE(IMG))),'-150x150.',SUBSTRING_INDEX(IMG, '.', -1)) AS IMG FROM (
SELECT    
p.`post_title` AS TITRE, 
(SELECT `meta_value` FROM wp_postmeta WHERE `post_id` = p.`ID` and `meta_key`='_yoast_wpseo_metadesc') AS DESCR,
p.`guid` AS URL,
(SELECT `guid` FROM wp_posts WHERE id = m.meta_value) AS IMG
FROM wp_posts p, wp_postmeta m
WHERE p.post_type =  'post'
AND p.post_status =  'publish'
AND p.id = m.post_id
AND m.meta_key =  '_thumbnail_id') TT

where DESCR is not null

Answer 2

The following query, adapted from the above, solved my particular problem which was simply to grab the last four posts and their featured images. Plus the post_name from which I could construct a pretty URL

SELECT title, post_name, date, content, CONCAT(LEFT(image, LENGTH(image) - LOCATE('.', REVERSE(image))),'-150x150.',SUBSTRING_INDEX(image, '.', -1)) AS image
FROM (
  SELECT    
  p.post_title AS title, 
  p.post_status AS 'status', 
  p.post_date AS date,
  p.post_content AS content,
  p.post_name AS post_name,
  (SELECT `guid` FROM wp_posts WHERE id = m.meta_value) AS image
  FROM wp_posts p, wp_postmeta m
  WHERE p.post_type = 'post'
  AND p.post_status = 'publish'
  AND p.id = m.post_id
  AND m.meta_key = '_thumbnail_id'
  ORDER BY date DESC
  LIMIT 4
) TT

Of course from there it's easy to make an excerpt etc using:

for($i=0; $i< $num_rows; $i++){  
  $post_content = mysql_result($query_result, $i, "content"); 
  $post_excerpt = substr($post_content, 0, 90); 
  $post_permalink = $post_url . mysql_result($query_result, $i, "post_name");

  echo $post_permalink; //etc

}

Answer 3

You can try this query for thumbnail size , for medium image i am not sure about the right size if you know the dimension then make custom alias as i made below using the SUBSTRING_INDEX to get the extension of file then i have used CONCAT function with the post_name column and the dimensions + extension ,similarly you can do this for medium size , As all upload goes to the upload folder you can analyze the generated thumbs name are original attachment name + -150x150 or other dimensions so from this logic your thumbs get the name with the dimensions, the attachments of post are stored in post_meta with the post id and having key name _wp_attachment_metadata which stores all the information about different sizes of file but in a serialized form so in mysql query you cannot unserialize the data

SELECT    
CONCAT(p.`post_name` ,'-150x150.',
SUBSTRING_INDEX(( SELECT `guid` FROM wp_posts WHERE id = m.meta_value ), '.', -1) )    
 AS `thumbnail`,
 (SELECT guid FROM wp_posts WHERE id = m.meta_value ) AS `full`
FROM wp_posts p, wp_postmeta m
WHERE p.post_type =  'post'
AND p.post_status =  'publish'
AND p.id = m.post_id
AND m.meta_key =  '_thumbnail_id'

This query works for me to get thumbnail of size 150*150 hope it works for you also