Cấu trúc cơ sở dữ liệu MySql cho:Tìm kiếm dựa trên cột đơn và giá trị khác nhau

hãy thử cái này:

create table City
    (
     Id int,
     Name varchar(50)
    );

    insert into City (Id, Name) 
    VALUES 
    (1, 'Toronto'), 
    (2, 'Chicago')

    create table Libraries(
    Id int,
    Name varchar(50),
    CityId int
    );

    insert into Libraries (Id, Name, CityId) 
    VALUES 
    (1, 'Toronto Library 1', 1),
    (2, 'Toronto Library 2', 1),
    (3, 'Chicago Library 1', 2),
    (4, 'Chicago Library 2', 2)

    create table Books(
    Id int,
    Isbn varchar(12),
    LibraryId int
    );

    insert into Books (Id, Isbn, LibraryId) 
    Values
    (1, '1234567891', 1),
    (2, '13344555', 1),
    (3, 'x123sada', 1),
    (4, 'xasdsadas', 2),
    (5, 'axxzksda', 2)

    select DISTINCT b.Name 
    from Books a
    inner join Libraries b
    on a.LibraryId = b.Id
    where Isbn in ('1234567891', '13344555')
    and b.CityId = 1

Chỉnh sửa:hoặc 4NF:

create table City
(
 Id int,
 Name varchar(50)
);

insert into City (Id, Name) 
VALUES 
(1, 'Toronto'), 
(2, 'Chicago')

create table Libraries(
Id int,
Name varchar(50),
CityId int
);

insert into Libraries (Id, Name, CityId) 
VALUES 
(1, 'Toronto Library 1', 1),
(2, 'Toronto Library 2', 1),
(3, 'Chicago Library 1', 2),
(4, 'Chicago Library 2', 2)

create table Books(
Id int,
Isbn varchar(12),
);

insert into Books (Id, Isbn) 
Values
(1, '1234567891'),
(2, '13344555'),
(3, 'x123sada'),
(4, 'xasdsadas'),
(5, 'axxzksda')

create table LibraryBooks
(
LibraryId int,
BookId int
);

insert into LibraryBooks (LibraryId, BookId)
VALUES
(1, 1),
(1, 2),
(3, 1),
(2, 4),
(5, 2)

select DISTINCT c.Name
from Books a
inner join LibraryBooks b
on a.Id = b.BookId
inner join Libraries c on
c.Id = b.LibraryId
where Isbn in ('1234567891', '13344555')
and c.CityId = 1