从数据库中挑选每月只出现一次的数据

Question

我有一张表，里面记录了银行的交易。我想把每个月只做一次交易的用户拉出来。这意味着他们当月的交易计数==为1。

我正在录制card_number、时间戳等。

Answer 1

SELECT * 
FROM transactions
GROUP BY card_number, month
HAVING COUNT(card_number) = 1

Answer 2

检查此

select     Card_Number,
           DATEPART(m, [TimeStamp] )MonthNo,
           COUNT(1) TxnCount
from       Transactions
group by   Card_Number,
           DATEPART(m, [TimeStamp] )
having     COUNT(1)=1

我假设您的表结构类似于下面的内容。

Card_Number int, 
TimeStamp  datetime