我有一個(gè)表,使用3個(gè)外鍵到其他表.當(dāng)我執(zhí)行左連接時(shí),我會(huì)收到重復(fù)的列.

MySQL表示,USING語(yǔ)法將減少重復(fù)的列,但沒(méi)有多個(gè)鍵的示例.

鑒于：

mysql> describe recipes;

+------------------+------------------+------+-----+---------+-------+

| Field | Type | Null | Key | Default | Extra |

+------------------+------------------+------+-----+---------+-------+

| ID_Recipe | int(11) | NO | PRI | NULL | |

| Recipe_Title | char(64) | NO | | NULL | |

| Difficulty | int(10) unsigned | NO | | NULL | |

| Elegance | int(10) unsigned | NO | | NULL | |

| Quality | int(10) unsigned | NO | | NULL | |

| Kitchen_Hours | int(10) unsigned | NO | | NULL | |

| Kitchen_Minutes | int(10) unsigned | NO | | NULL | |

| Total_Hours | int(10) unsigned | NO | | NULL | |

| Total_Minutes | int(10) unsigned | NO | | NULL | |

| Serving_Quantity | int(10) unsigned | NO | | NULL | |

| Description | varchar(128) | NO | | NULL | |

| ID_Prep_Text | int(11) | YES | | NULL | |

| ID_Picture | int(11) | YES | | NULL | |

| Category | int(10) unsigned | NO | | NULL | |

| ID_Reference | int(11) | YES | | NULL | |

+------------------+------------------+------+-----+---------+-------+

15 rows in set (0.06 sec)

mysql> describe recipe_prep_texts;

+------------------+---------------+------+-----+---------+-------+

| Field | Type | Null | Key | Default | Extra |

+------------------+---------------+------+-----+---------+-------+

| ID_Prep_Text | int(11) | NO | PRI | NULL | |

| Preparation_Text | varchar(2048) | NO | | NULL | |

+------------------+---------------+------+-----+---------+-------+

2 rows in set (0.02 sec)

mysql> describe recipe_prep_texts;

+------------------+---------------+------+-----+---------+-------+

| Field | Type | Null | Key | Default | Extra |

+------------------+---------------+------+-----+---------+-------+

| ID_Prep_Text | int(11) | NO | PRI | NULL | |

| Preparation_Text | varchar(2048) | NO | | NULL | |

+------------------+---------------+------+-----+---------+-------+

2 rows in set (0.02 sec)

mysql> describe mp_references;

+--------------+---------+------+-----+---------+-------+

| Field | Type | Null | Key | Default | Extra |

+--------------+---------+------+-----+---------+-------+

| ID_Reference | int(11) | NO | PRI | NULL | |

| ID_Title | int(11) | YES | | NULL | |

| ID_Category | int(11) | YES | | NULL | |

+--------------+---------+------+-----+---------+-------+

3 rows in set (0.00 sec)

我的查詢(xún)語(yǔ)句：

SELECT *

FROM Recipes

LEFT JOIN (Recipe_Prep_Texts, Recipe_Pictures, mp_References)

ON (

Recipe_Prep_Texts.ID_Prep_Text = Recipes.ID_Prep_Text AND

Recipe_Pictures.ID_Picture = Recipes.ID_Picture AND

mp_References.ID_Reference = Recipes.ID_Reference

);

我的目標(biāo)是從連接中獲取一行不含重復(fù)列的所有列.我使用MySQL C連接器發(fā)送SQL語(yǔ)句并檢索結(jié)果集.我相信C連接器有重復(fù)列名的問(wèn)題.

那么我應(yīng)該使用什么是SQL語(yǔ)句語(yǔ)法？

總結(jié)

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