need help in writing complex sql query with join and with case - mysql

Question

Here is SQL Fiddle
Expected output is below:
id | firstname. | lastname. | country.| followerscount.| followingcount.| BottonText
------------------------------------------------------------------------------------
54 prince lal nepal 1 1 Unfollow
56. Rekha. Gupta United States 1 0 Unfollow
57. Nirmal null null 0 1 Follow Back
I tried below query assuming current logged in UserId= 55 & compare with other users. Can you write the correct query, it can be with join, i just need the output,query can be anything
TRY1
SELECT
u.user_id AS id, u.first_name AS firstname,u.last_name AS lastname,u.country as country,
(select count(uf.following_user_id) from user_follow uf where uf.followed_user_id=u.user_id)as followerscount,
(select count(uf.followed_user_id) from user_follow uf where uf.following_user_id=u.user_id)as followingcount,
CASE
WHEN uuf.following_user_id=55 AND uuf.followed_user_id=u.user_id THEN "Unfollow" # A is following B == unfollow
WHEN uuf.following_user_id=u.user_id AND uuf.followed_user_id NOT IN(55) THEN "Follow Back" #B is following A but A is not following B = followBack
ELSE "Follow"
END AS BottonText
FROM userdetails u,user_follow uuf
WHERE u.user_id NOT IN(55) AND u.record_status=1
TRY2
SELECT
u.user_id,
(count(uf.following_user_id)) as followers,
CASE
WHEN uf.following_user_id=55 AND uf.followed_user_id=u.user_id THEN "Unfollow" # A is following B == unfollow
WHEN uf.following_user_id=u.user_id AND uf.followed_user_id=55 AND uf.following_user_id !=55 AND uf.followed_user_id !=u.user_id
THEN "Follow Back" #B is following A but A is not following B = followBack
ELSE "Follow"
END AS BottonText,
(select count(uf.followed_user_id)
from user_follow uf
where uf.following_user_id = u.user_id) as following
from
(userdetails u left outer join user_follow uf on uf.followed_user_id=u.user_id)
where u.record_status=1 and u.user_id NOT IN(55)
group by u.user_id
Table defination
CREATE TABLE `userdetails` (
`user_id` int(11) NOT NULL,
`first_name` varchar(50) NOT NULL,
`last_name` varchar(50) DEFAULT NULL,
`country` varchar(30) DEFAULT NULL,
`avatar_img_name` varchar(30) DEFAULT NULL,
`record_status` int(1) NOT NULL COMMENT '1- active'
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
ALTER TABLE `userdetails`
ADD PRIMARY KEY (`user_id`);
CREATE TABLE `user_follow` (
`id` int(11) NOT NULL,
`following_user_id` int(11) NOT NULL,
`followed_user_id` int(11) NOT NULL,
`created_date` datetime NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
#following_user_id and followed_user_id are foriegn key associated userdetails user_id

Answer 1

http://sqlfiddle.com/#!9/90d4ac/18
schema:
CREATE TABLE `userdetails` (
`user_id` int(11) NOT NULL,
`first_name` varchar(50) NOT NULL,
`last_name` varchar(50) DEFAULT NULL,
`country` varchar(30) DEFAULT NULL,
`avatar_img_name` varchar(30) DEFAULT NULL,
`record_status` int(1) NOT NULL COMMENT '1- active'
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
ALTER TABLE `userdetails`
ADD PRIMARY KEY (`user_id`);
INSERT INTO `userdetails` (`user_id`, `first_name`, `last_name`, `country`, `avatar_img_name`, `record_status`) VALUES
(1, 'Admin', 'Admin', 'India', NULL, 0),
(54, 'Prince', 'Lal', 'Nepal', 'p.jpg', 1),
(55, 'ashutosh', 'Singh', 'Afganistan', 'a.jpg', 1),
(56, 'Rekha', 'Gupta', 'United States', 'r.jpg', 1),
(57, 'Nirmal', NULL, NULL, NULL, 1);
CREATE TABLE `user_follow` (
`id` int(11) NOT NULL,
`following_user_id` int(11) NOT NULL,
`followed_user_id` int(11) NOT NULL,
`created_date` datetime NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO `user_follow` (`id`, `following_user_id`, `followed_user_id`, `created_date`) VALUES
(1, 55, 56, '2021-02-07 02:14:26'),
(2, 55, 54, '2021-02-06 01:14:26'),
(3, 54, 55, '2021-02-07 10:33:45'),
(4, 57, 55, '2021-02-07 00:00:00');
ALTER TABLE `user_follow`
ADD PRIMARY KEY (`id`),
ADD KEY `following_user_id` (`following_user_id`),
ADD KEY `followed_user_id` (`followed_user_id`);
ALTER TABLE `user_follow`
MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=5;
ALTER TABLE `user_follow`
ADD CONSTRAINT `user_follow_ibfk_1` FOREIGN KEY (`followed_user_id`) REFERENCES `userdetails` (`user_id`) ON DELETE CASCADE ON UPDATE CASCADE,
ADD CONSTRAINT `user_follow_ibfk_2` FOREIGN KEY (`following_user_id`) REFERENCES `userdetails` (`user_id`) ON DELETE CASCADE ON UPDATE CASCADE;
COMMIT;
query:
SELECT
u.user_id, u.first_name, u.last_name, u.country,
(SELECT COUNT(*) FROM user_follow uf1 WHERE uf1.followed_user_id=u.user_id) AS followerscount,
(SELECT COUNT(*) FROM user_follow uf2 WHERE uf2.following_user_id=u.user_id) AS followingcount,
IF(
EXISTS(SELECT * FROM user_follow uf3 -- if I'm following the specified user
WHERE uf3.following_user_id=55 AND uf3.followed_user_id=u.user_id),
'Unfollow', -- then show 'unfollow button'
IF(
EXISTS(SELECT * FROM user_follow uf4 -- if the specified user is following me
WHERE uf4.followed_user_id=55 AND uf4.following_user_id=u.user_id),
'Follow Back', -- then show 'follow back button'
'Follow') -- then show 'follow button'
) AS ButtonText
FROM
userdetails u
WHERE
u.user_id<>55
AND u.user_id<>1 -- should not select the admin user
explanation: it seems that the expected table is based on "userdetails" table, so you should only select "userdetails" in FROM clause, and add other column with subquery in SELECT clause