如何在同一个表中获取多个列值的数据匹配

Question

如何获取属于国家/地区79和作者80以及出版商91

的图书的ID

SELECT id FROM books WHERE ( 
    (filter = 'country' AND cat = 79) 
        AND
    (filter = 'author' AND cat = 80)
        AND
    (filter = 'publisher' AND cat = 91)
    )   

这是我的表结构

+----+----------+-----+
| ID | FITER    | CAT |
+----+----------+-----+
|  1 | country  | 79  |
|  1 | author   | 80  |
|  1 | publisher| 91  |
|  2 | country  | 476 |
|  2 | author   | 85  |
|  2 | publisher| 121 |
+----+----------+-----+         

谢谢

Answer 1

这是这种表结构的问题，你真的有那么多的过滤器，它们不能自己成为列吗？无论如何，它会是这样的：

SELECT DISTINCT id 
FROM books b
WHERE filter = 'country' AND cat = 79
AND EXISTS( SELECT 1 FROM books 
            WHERE filter = 'author' AND cat = 80
            AND id = b.id)
AND EXISTS( SELECT 1 FROM books 
            WHERE filter = 'publisher' AND cat = 91
            AND id = b.id);