MySQL Multi-Join Query - php

Question

I have multiple tables I am trying to grab data from in a single query. I seem to be close to a solution but can not seem to get the data result I am expecting.
Examples of my tables are as follows (fields have been truncated):
Table c
id
name
abbreviation
Table mr (relationship table tat ties tables c and m together by ID)
id
c.id
m.id
Table m
id
Table cnt
id
c.id
Table cmp
id
cnt.id
active
What I WANT is all fields from C, all fields from M where m.id = c.id, all active (active = 1) id's from CMP that match on cnt.id.
My most recent query (after dozens of iterations) is:
SELECT c.id AS id
, c.name AS name
, c.abbreviation AS abbr
, c.active AS active
, c.last_modified AS last_modified
, c.modified_by AS modified_by
, mr.media_id
, mr.related_object_table
, mr.related_object_id
, m.orig_name AS img_name
, m.unique_name AS img_slug
, m.file_type AS confed_file_type
, m.file_size AS file_size
, COUNT('cmp.id') AS comps
FROM confederations AS c
LEFT JOIN media_relationships AS mr
ON mr.related_object_id = c.id
AND mr.related_object_table = 'confederations'
LEFT JOIN media AS m
ON m.id = mr.media_id
INNER JOIN countries AS cnt
ON cnt.confederations_id = c.id
INNER JOIN competitions AS cmp
ON cmp.countries_id = cnt.id
AND cmp.active = 1;
I am not proficient with Joins.
Basically, the result i am expecting is: For each Confederation (table C) I want that confederations name, abbreviation, active status (active), last modified date, modified by; from the Media Relationship table (table MR) I want the image id associated with that confederation so I can use that id to grab the image name and image slug for the confederations primary image from the Media table (M).
Now I also want the total number of Competitions (table CMP) for a given Confederation. Competitions are stored with a Country ID that is tied to the primary key ID of a country in the Countries Table (table CNT). Each Country in table CNT has a Confederations ID. So to get the total number of Competitions per Confederation I am 'trying' to get all Countries within their respective Confederation by CONFEDERATIONS_ID in table CNT, then foreach confederation I want select all the competitions from table CMP with matching COUNTRIES_ID from the group of country id's for that given confederation. (At this point i think i am confusing myself with how to get what i want)
Somehow I am getting the CORRECT NUMBER of competitions, but I am getting duplicate Confederations as results. For Example I am getting something similar to this (assume I have 3 different confederations with 2, 1, and 3 competitions respectively):
Competitions 1 : name 1 | abbreviation 1 | image 1 | total competitions = 2;
Competitions 1 : name 1 | abbreviation 1 | image 1 | total competitions = 1;
Competitions 1 : name 1 | abbreviation 1 | image 1 | total competitions = 3
What am i doing wrong?

Answer 1

Through trial and error, I actually solved this on my own. I came back to post my answer and see Degan's answer, and though it is written differently than mine I think its very close to what I ended up with:
SELECT
cnf.id AS confed_id, cnf.name AS confed_name, cnf.abbreviation AS
confed_abbr, cnf.active AS confed_active, cnf.modified_by AS
confed_mod_by, cnf.last_modified AS confed_last_mod,
COUNT(cnt.id) AS total_countries,
COUNT(cmp.id) AS total_comps,
mr.media_id, mr.related_object_table, mr.related_object_id,
mr.primary_img,
m.orig_name AS img_name, m.unique_name AS img_slug, m.file_type AS file_type
FROM confederations AS cnf
LEFT JOIN media_relationships AS mr
ON mr.related_object_id = cnf.id AND mr.related_object_table = 'confederations'
LEFT JOIN media AS m
ON m.id = mr.media_id
LEFT JOIN countries AS cnt
ON cnt.confederations_id = cnf.id AND cnt.active = 1
LEFT JOIN competitions AS cmp
ON cmp.countries_id = cnt.id AND cmp.active = 1
GROUP BY cnf.id
So farthis seems to be giving me results i can use. I am not certain if my choice of Left Join for all my joins is in fact giving me everything i need (it SEEMS to be) and whether this will omit/add records once the tables get larger. If anyone can point out a problem in my query and my choice of using Left Join as opposed to a combination of LEFT and INNER JOINs as Degan did, that would be helpful.

Answer 2

When aggregating you need to group by.
Perhaps this is close to what you are looking for:
SELECT c.id AS id
, c.name AS name
, c.abbreviation AS abbr
, m.orig_name AS img_name
, SUM('cmp.id') AS comps
FROM confederations AS c
LEFT JOIN media_relationships AS mr
ON mr.related_object_id = c.id
AND mr.related_object_table = 'confederations'
LEFT JOIN media AS m
ON m.id = mr.media_id
INNER JOIN countries AS cnt
ON cnt.confederations_id = c.id
INNER JOIN competitions AS cmp
ON cmp.countries_id = cnt.id
AND cmp.active = 1
GROUP BY c.id AS id
, c.name AS name
, c.abbreviation AS abbr
, m.orig_name AS img_name