所以我是 MySQL 的新手。我創建了一個資料庫，其中包含我的圖書收藏。它有書名、體裁、卷數和書型（漫畫、輕小說、普通小說等）。到目前為止，這是我用于創建資料庫和添加資料的代碼。
create database books;
use books;
create table books_in_my_possession (title varchar(100), genre varchar(100), volume varchar (100));
insert into books_in_my_possession (title, genre, volume) values ('Assassins Creed Blade of Shao Jun', 'Historical Fiction', '1');
insert into books_in_my_possession (title, genre, volume) values ('Assassins Creed Blade of Shao Jun', 'Historical Fiction', '2');
insert into books_in_my_possession (title, genre,volume) values ('Torture Princess: Fremd Torturchen', 'Isekai', '1');
insert into books_in_my_possession (title, genre, volume) values ('Torture Princess: Fremd Torturchen', 'Dark Fantasy', '1');
alter table books_in_my_possession
add column book_type varchar(100);
update books_in_my_possession
set book_type = 'manga'
where title = 'Assassins Creed Blade of Shao Jun';
update books_in_my_possession
set book_type = 'light novel'
where title = 'Torture Princess: Fremd Torturchen';
我想做的是將“Torture Princess: Fremd Torturchen”和“1”（同名）按流派結合起來，這樣它就有“Isekai”和“Dark Fantasy”。我本可以在其中一個價值線中寫下“Isekai/Dark Fantasy”或“Isekai, Dark Fantasy”，但我希望將它們分開計算，因為書籍有多種型別。
我該怎么做呢？
uj5u.com熱心網友回復：
我認為您正在嘗試使用group_concat：https : //dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_group-concat
select title,
GROUP_CONCAT (genre) as genre,
volume,
book_type
from books.books_in_my_possession
group by title,volume,book_type ;
演示：https : //www.db-fiddle.com/f/7yUJcuMJPncBBnrExKbzYz/121
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