Wordpress custom QUERY - mysql

Question

I need to do select from Post table, each post is related to one category and on tag.
I need to select specific tag/s and/or category/s.
Terms table have custom field "menu_order", it is used to set category order.
I want to sort posts by that field.
If i do plain select:
SELECT * from wp_posts
LEFT
JOIN wp_term_relationships
ON ( wp_term_relationships.object_id = wp_posts.ID )
LEFT
JOIN wp_terms
ON ( wp_terms.term_id = wp_term_relationships.term_taxonomy_id )
WHERE 1=1
AND wp_posts.post_type = 'post'
AND (
wp_posts.post_status = 'publish'
OR wp_posts.post_status = 'private'
)
LIMIT 0, 20
I get result:
+----------------+----------------+----------+---------------------+
| POST ID | Term name | order | type |
+----------------+----------------+----------+---------------------+
| 2 | Fire | 1 | category |
+----------------+----------------+----------+---------------------+
| 2 | blue | 0 | tag |
+----------------+----------------+----------+---------------------+
That is just the intro.
If I do WHERE $wpdb->terms.term_id = 170 what is a TAG I have only one return.
+----------------+----------------+----------+---------------------+
| POST ID | Term name | order | type |
+----------------+----------------+----------+---------------------+
| 2 | blue | 0 | tag |
+----------------+----------------+----------+---------------------+
I need to select POSTS, filter out by category or/and tag, then get TERM_ORDER from category attached to POST.
So, no matter what results I have, order is always pulled from related category.
As I am not so strong in MYSQL, this gets me baffled. Any input would be helpful :)
UPDATE --------------------------------------------------
So, after crazy coding I managed to get what I wanted.
Do not hold your breath as this probably is ugly and slow, but works.
First, I create view where all products are collected.
$qqquery = "
CREATE VIEW samsam AS
SELECT
ID, post_content, post_title, post_excerpt, post_status, post_name, guid, post_type, $wpdb->term_relationships.term_taxonomy_id as cat_term_taxonomy_id, tt1.term_taxonomy_id as tag_term_taxonomy_id
FROM $wpdb->posts
LEFT
JOIN $wpdb->term_relationships
ON ( $wpdb->term_relationships.object_id = $wpdb->posts.ID )
LEFT
JOIN $wpdb->term_relationships AS tt1
ON ( tt1.object_id = $wpdb->posts.ID )
WHERE 1=1
AND $wpdb->posts.post_type = 'post'
AND (
$wpdb->posts.post_status = 'publish'
OR $wpdb->posts.post_status = 'private'
)
AND ( wp_term_relationships.term_taxonomy_id IN ( $query_cat ) // ID's of categories, seperated by coma
AND tt1.term_taxonomy_id IN (' . $add_query_tag_id . ') //ID's of POSTS seperated by coma
)
ORDER BY $wpdb->term_relationships.term_taxonomy_id DESC
";
$wpdb->query($qqquery);
After that I do query where I select view and join relationships and terms to get category order by filtering out order > 0, then group BY id to filter out duplicates.
$querystr = "
SELECT * from samsam
LEFT
JOIN $wpdb->term_relationships
ON (samsam.ID = $wpdb->term_relationships.object_id)
LEFT
JOIN $wpdb->terms
ON ($wpdb->terms.term_id = $wpdb->term_relationships.term_taxonomy_id)
AND ($wpdb->terms.menu_order > 0)
WHERE menu_order > 0
GROUP BY ID
ORDER BY menu_order ASC
LIMIT $item_limit_offset, $item_limit_pp"; // first is calculation of products to skip, second is how many posts per page
$pageposts = $wpdb->get_results($querystr, OBJECT);
What it does:
Category 1 (have order 1)
post
post
post
Category 3 (have order 2)
post
post
post
Category 2 (have order 3)
post
post
post
Can be limited, offseted, paginated, filtered out by tags and/or categories.
I used plugin "Term Menu Order" that adds extra field to order categories.
Have a nice day.

Answer 1

Why are you writing your own query here? Wordpress has built in functions to retrieve data.
http://codex.wordpress.org/Template_Tags/get_posts
http://codex.wordpress.org/Function_Reference/query_posts