Question

我有下表：

Transaction_ID  int(9)  NO  PRI NULL    auto_increment
Datetime    date    NO      NULL     
Giver_ID    int(9)  NO      NULL     
Recipient_ID    int(9)  NO      NULL     
Points  int(4)  NO      NULL     
Category_ID int(3)  NO      NULL     
Reason  text    NO      NULL

显然，我已经成功地为“行为周”奖励了一些学生的双倍积分。

我想要一个此transactions表中所有行的列表，其中单个用户（Recipient_ID）与Category_ID = 16有多个交易。

每个Recipient ID只应与Category_ID = 16进行一次交易。

例如，如果我有......

54784   2012-02-01  138573  137444  100 16  You have done very well in Behaviour Week! Because...
55040   2012-02-01  138573  132629  100 16  You have done very well in Behaviour Week! Because...

这是两个独立的用户，这很好。

但是，如果我找到......

54784   2012-02-01  138573  137444  100 16  You have done very well in Behaviour Week! Because...
55040   2012-02-01  138573  137444  100 16  You have done very well in Behaviour Week! Because...

然后我犯了一个错误，我需要删除其中一行。

有人可以建议一个查询，列出所有这些可能不正确的交易吗？我更喜欢他们只是为了“选择”，以便我可以手动检查而不是盲目地删除。

Answer 1

要查找类别16中具有多于1个事务的收件人ID，您可以使用以下内容：

select Recipient_ID,
       Count(Transaction_ID) as [Transactions]
from myTable
where Category_ID = 16
group by Recipient_ID
having Count(Transaction_ID) > 1

如果您想真正放心，请删除Having子句：

select Recipient_ID,
       Count(Transaction_ID) as [Transactions]
from myTable
where Category_ID = 16
group by Recipient_ID

然后，您可以查看针对每个收件人ID的交易数量，并确保每个

确实为1

Answer 2

您可以使用分组并拥有：

select count (transaction_id), recipient_id
from thetable
where category_id = 16
group by recipient_id
having count(transaction_id) > 1

having子句与where子句非常相似，但在分组发生后，它在行上运行。换句话说，where是一个预分组过滤器，having是一个后分组过滤器。

Answer 3

select Recipient_ID, COUNT(*)
from transactions
where Category_ID = 16
group by Recipient_ID
having COUNT(*) > 1

Answer 4

尝试

SELECT * FROM transactions WHERE category_id = 16 GROUP BY recipient_id HAVING COUNT(*)>1

这将仅显示具有多个这些条目的用户

查找具有重复事务的用户列表

4 个答案: