Count clause -> incorrect count value - mysql

Question

We have an issue using a counting combination with inner/left join that we cannot figure out how to solve.
We would appreciate any help on the matter!
We have 4 tables in the example:
1: providers: Including 2 providers
2: providers_categories: Including 2 categories. 1 provider can be in multiple categories (this seems to be causing the issue)
3: connections_providers: connecting the providers to the categories
4: reviews_providers: currently we have included 1 rating per provider
Goal: to output the review count from the table reviews_providers.
Issue: Provider 2 is included in 2 categories. The review count is doubled: 1 count for each provider category: A total of 2 reviews are printed even though only 1 entry exists.
Thank you!
Code:
SELECT prov.id, prov.title, prov_cat.title AS category, AVG(reviews.rating) AS rating, COUNT(reviews.rating) AS count
FROM connections_providers_categories conn
INNER JOIN providers_categories prov_cat
ON prov_cat.id = conn.category_id
LEFT JOIN reviews_providers reviews
ON reviews.provider_id = conn.provider_id
INNER JOIN providers prov
ON prov.id = conn.provider_id
GROUP BY prov.id
ORDER BY prov.title ASC
CREATE TABLE `connections_providers_categories` (
`provider_id` int(4) UNSIGNED NOT NULL,
`category_id` int(4) UNSIGNED NOT NULL
) ENGINE=MyISAM DEFAULT;
INSERT INTO `connections_providers_categories` (`provider_id`, `category_id`) VALUES
(1, 1),
(2, 1),
(2, 2);
CREATE TABLE `providers` (
`id` int(4) UNSIGNED NOT NULL AUTO_INCREMENT,
`title` varchar(100) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT;
INSERT INTO `providers` (`id`, `title`) VALUES
(1, 'Provider 1'),
(2, 'Provider 2');
CREATE TABLE `providers_categories` (
`id` int(4) UNSIGNED NOT NULL AUTO_INCREMENT,
`title` varchar(60) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT;
INSERT INTO `providers_categories` (`id`, `title`) VALUES
(1, 'Category 1'),
(2, 'Category 2');
CREATE TABLE `reviews_providers` (
`id` int(4) UNSIGNED NOT NULL AUTO_INCREMENT,
`provider_id` int(4) UNSIGNED NOT NULL,
`rating` enum('1','2','3','4','5') DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT;
INSERT INTO `reviews_providers` (`id`, `provider_id`, `rating`) VALUES
(1, 2, '5'),
(2, 1, '3');
Our question might resemble the following question, but we do not find the answer / see that it is the same case even thought both questions include multiple counts: count is multiplied after adding left join
It seems we might need a subquery, but we are not sure how to do this.
Any suggestions?
Thanks!

Answer 1

you can use subquery top get your result
SELECT prov.id, prov.title, GROUP_CONCAT(prov_cat.title) AS category, reviews.rating , reviews.count
FROM connections_providers_categories conn
INNER JOIN providers_categories prov_cat
ON prov_cat.id = conn.category_id
LEFT JOIN (SELECT provider_id, AVG(rating) AS rating, COUNT(provider_id) AS count FROM reviews_providers GROUP BY provider_id) reviews
ON reviews.provider_id = conn.provider_id
INNER JOIN providers prov
ON prov.id = conn.provider_id
GROUP BY prov.id,prov.title
ORDER BY prov.title ASC
id | title | category | rating | count
-: | :--------- | :-------------------- | -----: | ----:
1 | Provider 1 | Category 1 | 3 | 1
2 | Provider 2 | Category 2,Category 1 | 5 | 1
db<>fiddle here