python - 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'

但是当我尝试这个时：

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

我也遇到了这个问题。我把%d改成%s，就解决了。希望这对你有用。

Answer 2

问题是您没有在选择字符串中正确进行替换。来自文档：

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))

Answer 3

原因是您使用的是“%d”。当您在 SQL 中使用 '%' 时，执行会将 '%' 解释为格式。你应该这样写你的陈述：

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

Answer 4

根据您的 SQL 包，您可能需要cursor.statement改用。

Answer 5

使用 double %% 为我工作

  "SELECT  title, address from table t1, table t2 on t1.id=t2.id where t1.title like '%%Brink%%' "

Answer 6

from django.db import connection
print(connection.queries)

上面的代码应该显示对请求执行的所有请求。