Question

我试图创建一个查询，这样如果为一组订单订购了特定商品，我就可以让列显示Y / N.我要找的项目是OLI.id =＆＃39; 538＆＃39;。

所以我的结果是：

=IIF(DateInterval.Weekday = 1, 'Monday = Monday Last Week
DateAdd(DateInterval.Day, 2-WeekDay(Today), DateAdd(DateInterval.Day, -7, Today)),
    IIF(DateInterval.Weekday = 2, 'Tuesday = Monday Last Week
        DateAdd(DateInterval.Day, 2-WeekDay(Today), DateAdd(DateInterval.Day, -7, Today)),
            IIF(DateInterval.Weekday = 3, 'Wednesday = Monday Last Week
                DateAdd(DateInterval.Day, 2-WeekDay(Today), DateAdd(DateInterval.Day, -7, Today)),
                    IIF(DateInterval.Weekday = 4, 'Thursday = Monday Last Week
                        DateAdd(DateInterval.Day, 2-WeekDay(Today), DateAdd(DateInterval.Day, -7, Today)),
                            IIF(DateInterval.Weekday = 5, 'Friday = Monday This Week
                                DATEADD("d", 1 - DATEPART(DateInterval.WeekDay, Today,FirstDayOfWeek.Monday), Today),
                                    IIF(DateInterval.Weekday = 6, 'Saturday = Monday This Week
                                        DATEADD("d", 1 - DATEPART(DateInterval.WeekDay, Today,FirstDayOfWeek.Monday), Today),
                                            IIF(DateInterval.Weekday = 7, 'Sunday = Monday This Week
                                                DATEADD("d", 1 - DATEPART(DateInterval.WeekDay, Today,FirstDayOfWeek.Monday), Today),
                                                Today
                                            )
                                    )
                            )
                    )
            )
    )
)

我无法弄清楚我是否需要使用子查询或where exists函数？

这是我当前的疑问：

Order#, Customer#, FreightPaid
12345, 00112233, Y
12346, 00112233, N

Answer 1

我建议使用exists子句而不是join：

select ol.OrderID, ol.Accountuid as Customerno,
       (case when exists (select 1 
                          from Orderlog_item OLI join
                               Account A
                               on A.uid = OL.Accountuid
                          where OLI.orderlogkey = OL.[key] and A.GroupId = 'X9955'
                         )
             then 1 else 0
        end) as flag
from [SMILEWEB_live].[dbo].[OrderLog] OL
where OL.CreateDate >= GETDATE() - 60;

这可以防止出现一些问题。首先，当存在多个匹配行时会导致重复行（并且select distinct会增加不必要的开销）。第二，缺少行，当您使用内部联接而不是外部联接时会发生这种情况。

如果在详细信息表中找到记录，则显示Y / N列

1 个答案: