How to get how many chapters read by user in mysql - mysql

Question

I am having three tables bible_chapters, bible_reading_portions, user_bible_trackings, 1 chapter may have multiple bible portions and we are tracking portions in user_bible_trackings table. Below is my schema:-
bible_chapters
id chapter_name
1 Chpt1
2 Chpt2
3 Chpt3
bible_reading_portions
id bible_chapter_id portion_name
1 1 Chp1P1
2 2 Chp2P1
3 2 Chp2P2
4 2 Chp2P3
5 3 Chp3P1
user_bible_trackings
id bible_reading_portion_id user_id
1 1 1
2 2 1
3 3 1
4 4 1
5 1 1
6 2 1
7 3 1
8 4 1
9 1 1
10 2 1
So you see that above user_bible_trackings table user_id 1 have read Chpt1 3 times and Chpt2 2 times and user again started the chapter2 3rd time but its not complete yet beacuse chapt2 belongs to 3 portions,.... for the 3rd time user not read all the portions. So my expected output be like:-
user_id total_chapteres_read
1 5 // i.e means user read chpt1 3 times and chpt2 2 times so count will be 3+2=5
Can anyone help me how can i acheieve the same.
#Akina PLease check i have added the schema queries below:-
CREATE TABLE `bible_chapters` (
`id` int(11) NOT NULL,
`chapter_name` varchar(150) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
INSERT INTO `bible_chapters` (`id`, `chapter_name`) VALUES
(1, 'Chp1'),
(2, 'Chp2'),
(3, 'Chp3');
---------------------
CREATE TABLE `bible_reading_portions` (
`id` int(11) NOT NULL,
`bible_chapter_id` int(11) NOT NULL,
`portion_name` varchar(50) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
INSERT INTO `bible_reading_portions` (`id`, `bible_chapter_id`, `portion_name`)
VALUES
(1, 1, 'Chp1p1'),
(2, 2, 'Chp2p2'),
(3, 2, 'Chp2p2'),
(4, 2, 'Chp2p3');
-----------
CREATE TABLE `user_bible_trackings` (
`id` int(11) NOT NULL,
`bible_reading_portion_id` int(11) NOT NULL,
`user_id` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
INSERT INTO `user_bible_trackings` (`id`, `bible_reading_portion_id`, `user_id`) VALUES
(1, 1, 1),
(2, 2, 1),
(3, 3, 1),
(4, 4, 1),
(5, 1, 1),
(6, 2, 1),
(7, 3, 1),
(8, 4, 1),
(9, 1, 1),
(10, 2, 1);

Answer 1

WITH
cte1 AS (
SELECT ubt.user_id,
bc.id bc_id, bc.chapter_name,
brp.id brp_id, brp.portion_name,
COUNT(*) cnt
FROM bible_chapters bc
JOIN bible_reading_portions brp ON bc.id = brp.bible_chapter_id
JOIN user_bible_trackings ubt ON brp.id = ubt.bible_reading_portion_id
GROUP BY 1,2,3,4,5
),
cte2 AS (
SELECT user_id, bc_id,
COUNT(brp_id) portions_count,
MIN(cnt) complete_readings
FROM cte1
GROUP BY 1,2
)
SELECT user_id, SUM(complete_readings) total_readings
FROM cte2
GROUP BY 1
fiddle with some comments.
The solution does not check does all portions of a chapter were read. For to take this into account you must compare portions_count (added but not used) with the same value for a chapter (obtained in separate CTE).