Question

I have two tables word_term_relationships and word_posts

What I’m doing is using a while loop in order to fetch a certain record from the word_term_relationships table where a certain value is true.

$query = "SELECT object_id 
          FROM `word_term_relationships` 
          WHERE `term_taxonomy_id` = '54'"; 

I then use another query within the loop to use the data that was retrieved from the previous query in order to fetch data from the other table word_posts

$query2 = "SELECT post_title, post_date, post_date_gmt, guid 
           FROM `word_posts` 
           WHERE `ID` = '$post_id'";

This I can do and works fine.

The only issue is that I then need to order the results by date and time, I can do this without the while loop and using the ORDER BY function and the word_posts table.

However, I’ve tried to link the tables within the query like this (below) in order to order the data. But obviously it isn’t correct – I just can’t pinpoint within the query what is wrong.

$query = "SELECT word_term_relationships.object_id 
          FROM word_term_relationships 
          WHERE word_term_relationships.term_taxonomy_id = '54' 
          ORDER BY word_posts.post_date ASC";

I know the above query is missing something, I was thinking a second where after the ORDER BY word_posts.post_date ASC.

Answer 1

A simple INNER JOIN will solve your problem. Try this,

SELECT a.post_title, 
       a.post_date, 
       a.post_date_gmt, 
       a.guid 
FROM   word_posts a 
       INNER JOIN word_term_relationships b
           ON a.ID = b.object_id
WHERE  b.term_taxonomy_id= '54'
ORDER BY a.post_date ASC