充分利用數據庫表類似的行

Question

朋友你好我有 報價表如下表結構

我要訪問所有類似的報價（有相同的AUTHOR_ID和CATEGORY_ID）特定_id（ quoteId）

類似的引號表示同一個category_id和author_id相同的表中所有這些行的所有列。如果兩位作者的作者相同且類別相同，則可以將兩個引號視爲相似。

Answer 1

相同的作者ID和類別ID？

SELECT `related_quote`.* 
FROM `quote` AS `main_quote` 
LEFT JOIN `quote` AS `related_quote` USING(`author_id`, `category_id`) 
WHERE `main_quote`.`_id` = QUOTE_ID 

這會得到你原來的報價（即。QUOTE_ID）和所有與它相關的信息。

mysql> SELECT `related_quote`.* 
    -> FROM `quote` AS `main_quote` 
    -> LEFT JOIN `quote` AS `related_quote` USING(`author_id`, `category_id`) 
    -> WHERE `main_quote`.`_id` = 1; 
+------+----------------+-----------+-------------+ 
| _id | content  | author_id | category_id | 
+------+----------------+-----------+-------------+ 
| 1 | test   |   1 |   1 | 
| 2 | test related |   1 |   1 | 
| 3 | test related 2 |   1 |   1 | 
+------+----------------+-----------+-------------+ 
3 rows in set (0.01 sec) 

您可以通過簡單地增加

AND `related_quote`.`_id` != QUOTE_ID 

到查詢的末尾移除從ResultSet的QUOTE_ID。

Answer 2

select 
    q1.* 
from 
    quotes q1 
inner join 
    (select 
     author_id, 
     category_id 
    from 
     quotes 
    where 
     _id = 1) q2 
ON 
    q1.author_id = q2.author_id 
AND 
    q1.category_id = q2.category_id