错误:光标'对象没有属性'_last_executed

Question

我有这个光标

cursor.execute("SELECT price FROM Items WHERE itemID = ( 
                  SELECT item_id FROM Purchases 
                  WHERE purchaseID = %d AND customer_id = %d)", 
                  [self.purchaseID, self.customer])

我收到这个错误

'Cursor' object has no attribute '_last_executed'

但是,当我尝试这个:

cursor.execute("SELECT price FROM Items WHERE itemID = ( 
                  SELECT item_id FROM Purchases 
                  WHERE purchaseID = 1 AND customer_id = 1)", 
                  )

没有错误.我该如何解决？

Answer 1

我也遇到过这个问题.我将%d更改为%s,它就解决了.希望这对你有用.

Answer 2

问题是你没有在你的选择字符串中正确地进行替换.来自docs:

def execute(self, query, args=None):

    """Execute a query.

    query -- string, query to execute on server
    args -- optional sequence or mapping, parameters to use with query.

    Note: If args is a sequence, then %s must be used as the
    parameter placeholder in the query. If a mapping is used,
    %(key)s must be used as the placeholder.

    Returns long integer rows affected, if any

    """

所以,它应该是:

cursor.execute("SELECT price FROM Items WHERE itemID = ( 
              SELECT item_id FROM Purchases 
              WHERE purchaseID = ? AND customer_id = ?)", 
              (self.purchaseID, self.customer))