SQLite计数，按计数分组和排序（带分隔符|）

Question

我想在电影Genren中计算一个SQLITE数据库。

在数据库中以保存流派为例，以下是3个示例：

Genres
---------
Action 
Western|Crime
Drama|Western|Comedy|Horror

有人对我有解决方案吗？

Answer 1

问题仍然太模糊，但是为了纪念Stack Overflow上的“变得好”和“回答任何问题”，下面是一个解决方案的开始：

/*
DROP TABLE IF EXISTS movie;

CREATE TEMP TABLE movie
(id INTEGER NOT NULL UNIQUE PRIMARY KEY AUTOINCREMENT,
genres TEXT);

INSERT INTO movie (genres)
VALUES
   ('Action'),
   ('Western|Crime'),
   ('Drama|Western|Comedy|Horror');

*/

WITH RECURSIVE split AS (
     SELECT id, 
            0 AS num,
            instr(genres,'|') AS delimit,
            null AS genre, 
            genres AS remain
     FROM movie
     WHERE genres is not null
     UNION
     SELECT 
            id,
            num + 1 AS num,
            CASE WHEN delimit <= 0 THEN -1
                 ELSE instr(substr(remain, delimit + 1),'|') END AS delimit, 
            CASE WHEN delimit <= 0 THEN remain 
                 ELSE substr(remain, 1, delimit -1) END AS genre,
            CASE WHEN delimit <= 0 THEN null 
                 ELSE substr(remain, delimit + 1) END AS remain
     FROM split
     WHERE delimit >= 0
)
SELECT id, num, genre
FROM split
WHERE genre is not null
ORDER BY id, num;