Question

 Records = Cursor.execute("SELECT cust_addr1, cust_addr2, cust_postcode, cust_telno_home, cust_email \
                           FROM tblcustomer, tblpet \
                           WHERE cust_surname = ? and tblpet.pet_deceased = ?" ,(SearchCriteria[0], "Y")).fetchall()

我可以运行此查询，如果我删除tblpet完全正常，但当我添加tblpet查询运行但我得到结果重复。因此，取代5个结果，我有6300这样的东西，但所有相同的结果循环。

由于

修改

我已经修复了它，感谢 Mureinik 和 Siyual 告诉我有关联接的信息。然后我找到了这些

https://msdn.microsoft.com/en-us/library/bb243855(v=office.12).aspx

JOINing mdb tables with pyodbc

它工作了50％然后我有一个很好的想法进入访问并进行查询然后切换到SQL视图并复制它。它工作得很好，我是如此接近

ANSWER

 Records = Cursor.execute("""SELECT tblcustomer.cust_addr1, tblcustomer.cust_addr2,
                             tblcustomer.cust_postcode, tblcustomer.cust_telno_home, tblcustomer.cust_email
                             FROM tblcustomer INNER JOIN tblpet ON (tblcustomer.cust_no = tblpet.pet_cust_no)
                             WHERE cust_surname = ? and tblpet.pet_deceased = ?""", (SearchCriteria[0],"Y")).fetchall()

Answer 1

当您像在此处所做的那样编写隐式连接时（即，在from子句中有多个表），数据库会创建行的笛卡尔积。您需要添加条件以仅匹配适当的行。例如，假设客户有ID并且宠物具有客户的ID：

SELECT cust_addr1, cust_addr2, cust_postcode, cust_telno_home, cust_email
FROM   tblcustomer, tblpet
WHERE  tblcustomer.id = tblpet.customer_id AND -- Here!
       cust_surname = ? AND
       tblpet.pet_deceased = ?

或者更好的是，您可以使用显式join语法：

SELECT cust_addr1, cust_addr2, cust_postcode, cust_telno_home, cust_email
FROM   tblcustomer
JOIN   tblpet ON tblcustomer.id = tblpet.customer_id -- Here!
WHERE  cust_surname = ? AND
       tblpet.pet_deceased = ?

Pyodbc SQL SELECT Cursor.execute重复结果

1 个答案: