Question

我正在尝试使用SQL Server 2012 加入两个日志表，以便在记录操作时添加每个帐户的状态。

第一个表格是根据请求日期（request_date）和收件人<从网站的用户（向其他用户）发出的联系请求日志创建的报告/ strong>（receiver_account_id）请求。如果联系请求获得批准，则也会填充批准日期（approval_date）列。此表如下所示：

receiver_account_id sender_account_id request_date approval_date 13 19 2012-08-10 2012-09-01 13 21 2013-05-15 NULL 17 19 2011-09-11 NULL 25 44 2012-11-05 2012-11-07

第二个表基本上记录帐户的状态更改：

date account_id status 2011-07-10 13 free 2012-08-15 13 premium 2010-12-10 17 free 2012-05-05 17 premium 2010-01-20 25 free 2011-04-10 25 premium 2012-11-06 25 free

我想加入这两个表，所以我可以得到这样的结果：

receiver_account_id sender_account_id request_date approval_date receiver_status_when_received receiver_status_when_approved 13 19 2012-08-10 2012-09-01 free premium 13 21 2013-05-15 NULL premium NULL 17 19 2011-09-11 NULL free NULL 25 44 2012-11-05 2012-11-07 premium free

发件人的状态根本不重要。

Answer 1

试试这个

;WITH StatusPeriods AS
(
    SELECT account_id, [Status], [date] AS StatusStart, 
        ISNULL((SELECT MIN(Date) FROM status_log nxt WHERE nxt.date > sl.Date AND nxt.account_id = sl.account_id), '2100-1-1') AS StatusEnd
    FROM status_log sl
) 
SELECT request.*, 
    StatusWhenReceived.[Status] AS  receiver_status_when_received, StatusWhenApproved.[Status] AS receiver_status_when_approved
FROM requests 
INNER JOIN  StatusPeriods StatusWhenReceived 
    ON StatusWhenReceived.receiver_account_id = requests.account_id AND requests.request_date between StatusWhenReceived.StatusStart AND StatusWhenReceived.StatusEnd
LEFT  JOIN  StatusPeriods StatusWhenApproved 
    ON StatusWhenApproved.receiver_account_id = requests.account_id AND requests.approval_date between StatusWhenApproved.StatusStart AND StatusWhenApproved.StatusEnd

连接两个日志表以获取记录事件时帐户的状态

1 个答案: