如何获得对多列值的数据匹配在同一个表

Question

我如何得到那些属于国家79和笔者80和出版商的图书编号91

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

这里是我的表结构

+----+----------+-----+ 
| 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，他们不能对自己列？无论如何，这将是这样的：

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);