OR inside MySQL中的連接

Question

我想知道OR在JOIN內部出了什麼問題，因爲它似乎沒有響應兩個條件：(k0.keyword = 'Nombre' AND k0.value LIKE 'Cliente3') OR (k0.keyword = 'Nombre' AND k0.value = 'Cliente4'))。它總是返回完整的表格內容，並且應該只返回5組。我目前正在使用多個連接，我只是在測試一些東西，並提出這個問題，並希望瞭解這種行爲。

SELECT d.id, d.name, d.created, d.updated 
FROM documents d 
    INNER JOIN permissions p 
    ON (d.wfid = p.wfId AND d.docid = p.docId AND p.userid = 1) 
    INNER JOIN keywords k0 
    ON (k0.document_id = d.id AND (k0.keyword = 'Nombre' AND k0.value LIKE 'Cliente3') 
     OR (k0.keyword = 'Nombre' AND k0.value = 'Cliente4')) 
ORDER BY k0.value DESC, d.id DESC LIMIT 0, 12; 

+------+-----------------------------+---------------------+---------------------+ 
| id | name      | created    | updated    | 
+------+-----------------------------+---------------------+---------------------+ 
| 5355 | Documento - Digitalización | 2014-03-31 12:57:51 | 2014-03-31 12:57:51 | 
| 5354 | Documento - Digitalización | 2014-03-28 11:14:11 | 2014-03-28 11:14:11 | 
| 5270 | DOC2      | 2014-03-07 11:41:23 | 2014-02-25 13:41:57 | 
| 5269 | DOC2      | 2014-03-07 11:41:23 | 2014-02-25 12:39:51 | 
| 5268 | DOC2      | 2014-03-07 11:41:23 | 2014-02-25 12:39:25 | 
| 5267 | DOC1      | 2014-03-07 11:41:23 | 2014-02-25 12:39:10 | 
| 5266 | DOC1      | 2014-03-07 11:41:23 | 2014-03-06 01:35:16 | 
| 5265 | DOC1      | 2014-03-07 11:41:23 | 2014-02-25 12:38:37 | 
| 5264 | DOC1      | 2014-03-07 11:41:23 | 2014-02-25 12:38:25 | 
| 5263 | DOC1      | 2014-04-07 11:23:00 | 2014-03-20 09:54:30 | 
| 5269 | DOC2      | 2014-03-07 11:41:23 | 2014-02-25 12:39:51 | 
| 5268 | DOC2      | 2014-03-07 11:41:23 | 2014-02-25 12:39:25 | 
+------+-----------------------------+---------------------+---------------------+ 
12 rows in set (0.00 sec) 

mysql> select * from keywords where keyword = 'Nombre'; 
+-------+-------------+---------+----------+ 
| id | document_id | keyword | value | 
+-------+-------------+---------+----------+ 
| 15888 |  5263 | Nombre | Cliente1 | 
| 15889 |  5264 | Nombre | Cliente1 | 
| 15890 |  5265 | Nombre | Cliente1 | 
| 15891 |  5266 | Nombre | Cliente2 | 
| 15892 |  5267 | Nombre | Cliente3 | 
| 15893 |  5268 | Nombre | Cliente3 | 
| 15894 |  5269 | Nombre | Cliente3 | 
| 15895 |  5270 | Nombre | Cliente4 | 
+-------+-------------+---------+----------+ 
8 rows in set (0.00 sec) 

Answer 1

我認爲你的OR標準是微不足道的。嘗試移動圓括號：

k0.document_id = d.id AND 
((k0.keyword = 'Nombre' AND k0.value LIKE 'Cliente3') OR 
    (k0.keyword = 'Nombre' AND k0.value = 'Cliente4')) 

這應該讓您的連接保持機智。

Answer 2

由於您的兩個條款都檢查了k0.keyword = 'Nombre'，爲什麼不簡單地使用IN代替k0.value？

INNER JOIN keywords k0 ON k0.document_id = d.id 
    AND k0.keyword = 'Nombre' 
    AND k0.value IN ('Cliente3', 'Cliente4')