annotate() 添加超出需要的内容

Question

我的 annotate(sum()) 函数遇到一个小问题。现在我想要它做的是显示列表内给定计划中所有到期日的总计。对于第一个来说它确实如此。代码如下：

#get the invesments maturing this year
        for p in plans:
            cur_inv = Investment.objects.all().filter(plan = p).order_by('financial_institution').filter(maturity_date__year = current_year)
            nxt_inv = Investment.objects.all().filter(plan = p).order_by('financial_institution').filter(maturity_date__year = next_yr)
            thr_inv = Investment.objects.all().filter(plan = p).order_by('financial_institution').filter(maturity_date__year = thr_yr)
            fr_inv = Investment.objects.all().filter(plan = p).order_by('financial_institution').filter(maturity_date__year = fr_yr)
            fv_inv = Investment.objects.all().filter(plan = p).order_by('financial_institution').filter(maturity_date__year = fv_yr)

            for inv in cur_inv:
                total += inv.amount or 0
            for inv in cur_inv:
                total_m += inv.maturity_amount or 0

            for inv in nxt_inv:
                total2 += inv.amount or 0
            for inv in nxt_inv:
                total_m2 += inv.maturity_amount or 0

            for inv in thr_inv:
                total3 += inv.amount or 0
            for inv in thr_inv:
                total_m3 += inv.maturity_amount or 0

            for inv in fr_inv:
                total4 += inv.amount or 0
            for inv in fr_inv:
                total_m4 += inv.maturity_amount or 0

            for inv in fv_inv:
                total5 += inv.amount or 0
            for inv in fv_inv:
                total_m5 += inv.maturity_amount or 0

#Calculate the holding totals with each company
            total_list = p.investment_set.filter(maturity_date__gte= '%s-1-1' % current_year).values('financial_institution__abbr').annotate(Sum('maturity_amount')).order_by('financial_institution__abbr')
            gtotal = total_m + total_m2 + total_m3 + total_m4 + total_m5

            plan_list.append({
                'plan':p,
                'investment': cur_inv,
                'nxt_inv': nxt_inv,
                'thr_inv': thr_inv,
                'fr_inv': fr_inv,
                'fv_inv': fv_inv,
                'total_list': total_list,
                'grand': gtotal,
            })

我现在唯一的问题是，当它进入下一个计划时，它会继续添加到总计中，而不是回到 0。

我错过了什么吗？

任何帮助将不胜感激。

谢谢

Answer 1

您将 += 与 total_m* 变量一起使用，但从未在循环中将它们重置为 0。它们不会仅仅因为新的迭代已经开始而自动重置。

FWIW，您应该尝试在这里优化您的代码。您正在生成 6*len(plans) 查询，这可能会相当昂贵。