Question

I am improving my php script which has two simple sql queries. What Im trying to do is to combine the two queries into one.

1st query:

SELECT categories.*, entries.* 
FROM categories, entries 
WHERE entries.cat_id = categories.cat_id 
ORDER BY dateposted ASC 
LIMIT 5;

2nd query:

SELECT comments.* 
FROM comments 
WHERE comments.entry_id = '. $row['id'].';

These two work great when separate. I just need to combine them into one(still simple, no UNION or INNER JOINs please) and possibly count a number of comments for a particular entry right in the query.
Also, my “comments” table has five columns (comment_id, post_id, author, body, dateposted) if this is any helpful to know.

I tried different ways. Something like this:

SELECT categories.*, entries.*, COUNT(comments.entry_id) AS comm_num 
FROM categories, entries, comments 
WHERE entries.cat_id = categories.cat_id 
AND comments.entry_id = entries.id 
ORDER BY dateposted ASC LIMIT 5;

did not work…

Any help will be greatly appreciated.

Answer 1

Your first query is essentially a join, and it may not be any faster. You can query for entries (while displaying the corresponding category information) like so:

SELECT entries.*, categories.* 
FROM entries
LEFT JOIN categories ON entries.cat_id = categories.cat_id 
ORDER BY dateposted ASC 
LIMIT 5;

Also, it sounds like you don’t actually want to return each comment row in this query, but rather just obtain a comment count per “entry”. For that count, you can likely do this:

SELECT entries.*, categories.*, COUNT(comments.comment_id) AS comm_num  
FROM entries
LEFT JOIN categories on entries.cat_id = categories.cat_id
LEFT JOIN comments on comments.entry_id = entries.entry_id
GROUP BY entries.entry_id
ORDER BY dateposted ASC 
LIMIT 5;

Note the COUNT function is counting comment IDs, not entry IDs.