Question

我很难参考MS访问查询中的先前记录。我知道Dlockup但问题是：我想使用[TransactionID]字段引用事务表中的先前记录，但该表中的事务属于Customers表中的许多客户。因此，如果我只是使用[TransactionID]字段在交易表中请求先前的记录，它将只给我以前的记录，即使它属于另一个客户而且我不想要的。我现在就用这个

# Experimental data stored in lists: time_aralist and orienrad_aralist
# List stores the segments as arrays

fig = plt.figure()

# Finding curve fit
fittime_aralist, fitorienrad_aralist, fitorienrad_funclist = [], [], []
for j in range(len(time_aralist)):
    z, res, _, _, _ = np.polyfit(time_aralist[j], orienrad_aralist[j], 200, full=True)
    orienrad_func = np.poly1d(z)
    fittime_ara = np.linspace(time_aralist[j][0], time_aralist[j][-1], 10000)
    fitorienrad_ara = orienrad_func(fittime_ara)

    # Appending to list
    fittime_aralist.append(fittime_ara)
    fitorienrad_aralist.append(fitorienrad_ara)
    fitorienrad_funclist.append(orienrad_func)

# Plotting experimental data
for j in range(len(time_aralist)):
    plt.plot(time_aralist[j], orienrad_aralist[j], 'ro')
for j in range(len(fittime_aralist)):
    plt.plot(fittime_aralist[j], fitorienrad_aralist, 'k-')

但是，我不知道如果只添加前一条记录属于同一[CustomerID]的话，如何添加一个说这样做的部分？！就像我想要的东西：

Expr1: DLookUp("[TheFieldThatIWantItsPreviousValue]",
"TheQueryThatHavingTheTwoTablesTogether","[TransactionID]=" & [TransactionID]-1)

或喜欢

Expr1: DLookUp("[TheFieldThatIWantItsPreviousValue]",
"TheQueryThatHavingTheTwoTablesTogether","[TransactionID]=" & [TransactionID]-1) where [CutomerID] = [CutomerID]

我非常感谢你的帮助，先感谢您，大卫。

Answer 1

您正在寻找属于该客户的最大TransactionID，它低于当前客户：

DLookUp("TheFieldThatIWantItsPreviousValue]", "TheQuryThatHavingTheTwoTablesTogether", 
    "[TransactionID]=" & DMax(... see above ...))

然后将结果反馈到原始的DLookUp调用中：

Promise.all()

引用MS访问查询中的先前记录

1 个答案: