how find related inventory using multiple searching criteria in PHP? - php

Question

Is there any way I could use php+mysql to do multiple criteria search?
I saw it on a website, and i want to make something similar for myself.
So I have two tables
table1- 'Books' (title, author, BookID)
table2- 'Descriptions' (Bookid, descriptions)
Each book can have as many descriptions as the users want it to have.
Table 'Books'
Title Author BookID
Nightmare (…) Tom B. AAA
Wonderful (…) Jim C. AAB
Ghost Night (…) Amy D. AAC
Babysitter (…) Kitty D. AAD
Hello world (…) Pete P. AAE
Hannibal (…) Butter H. AAF
and
table 'Descriptions'
Book ID Description Relevance
AAA Thriller 0
AAA Crime 0
AAA Detective 0
AAB Geography 0
AAB Travel 0
AAC Thriller 0
AAD Comedy 0
AAD Family 0
AAE Programming 0
AAE Computer Science 0
AAF Thriller 0
AAF Crime 0
I have already made the insert data part, it's actually not that hard for me, but when it comes to the searching part, things become way more complicated than I thought it would be.
the sheet I'll be using is the exact same model my ‘target’ website uses,here i use () to represent html's select form, and [] to represent ordinary input form
[ ]
(AND/OR) [ ]
(AND/OR) [ ]
(AND/OR) [ ]
and users can fill it 1-4 criteria, for example, "thriller" (AND) "Crime", and the MySQL would find all the descriptions that fit these descriptions, in my case, it would be these informations:
AAA Thriller 0
AAA Crime 0
AAC Thriller 0
AAF Thriller 0
AAF Crime 0
And next step the computer should categorize the ID found and sort the results into this:
AAA 2 criteria verified
AAF 2 criteria verified
AAC 1 criteria verified
and after that, i want it to echo/print these information onto the browser:
1. Nightmare (…) Tom B. AAA
descriptions: Thriller, Crime
2. Hannibal (…) Butter H. AAF
descriptions: Thriller, Crime
3. Ghost Night (…) Amy D. AAC
descriptions: Thriller
my main problem is the categorizing and sorting part, and i don't know how to insert a code into another code in SQL.
I’ve tried GROUP BY (for the first time) and I didn’t make it.
in fact, after a few days of failed attempts, i started thinking if my data structure is the real problem...
thank you for your help and your attention.

Answer 1

Using a group by is a good idea, but you might want to add a count of catergories to help you to sort.
In example :
Schema (MySQL v5.7)
CREATE TABLE book (
`title` VARCHAR(10),
`id` VARCHAR(3) PRIMARY KEY
);
INSERT INTO book
(`title`, `id`)
VALUES
('Nightmare', 'AAA'),
('Wonderful.', 'AAB'),
('GhostNight', 'AAC'),
('Babysitter', 'AAD'),
('Helloworld', 'AAE'),
('Hannibal', 'AAF');
CREATE TABLE cat (
`BookID` VARCHAR(3),
`Description` VARCHAR(50),
`Relevance` VARCHAR(7),
FOREIGN KEY (`BookID`) REFERENCES book (id)
);
INSERT INTO cat
(`BookID`, `Description`, `Relevance`)
VALUES
('AAA', 'Thriller', '0'),
('AAA', 'Crime', '0'),
('AAA', 'Detective', '0'),
('AAB', 'Geography', '0'),
('AAB', 'Travel', '0'),
('AAC', 'Thriller', '0'),
('AAD', 'Comedy', '0'),
('AAD', 'Family', '0'),
('AAE', 'Programming', '0'),
('AAE', 'Computer Science', '0'),
('AAF', 'Thriller', '0'),
('AAF', 'Crime', '0');
Query #1
SELECT b.title, COUNT(c.description) AS cnt
FROM book b
LEFT JOIN cat c
ON b.id = c.BookID
WHERE c.Description IN ('Thriller', 'Crime')
GROUP BY b.title
ORDER BY cnt DESC;
Output
| title | cnt |
| ---------- | --- |
| Nightmare | 2 |
| Hannibal | 2 |
| GhostNight | 1 |
View on DB Fiddle