如何将SQL查询函数转换为django查询集

Question

我从.sql文件中获得以下示例查询，如何将其转换为django queryset：

这是我到目前为止所做的：

class AdjustmentView(generics.ListCreateAPIView):
    queryset = Adjustment.objects.all()
    serializer_class = AdjustmentSerializer

    def get_adjustment(self):
        Adjustment.objects.filter(employee_month_id=1,adjustment_type=2)
        .values('exchange_rate','amount').aggregate(Sum('amount', field="exchange_rate*amount") )

只是一个示例查询集即可。

CREATE OR REPLACE FUNCTION getAdjustment(int, int, int) RETURNS float AS $$
DECLARE
    adjustment float;
BEGIN

    IF ($3 = 1) THEN
        SELECT SUM(exchange_rate * amount) INTO adjustment
        FROM Employee_Adjustments
        WHERE (Employee_Month_ID = $1) AND (adjustment_type = $2);
    ELSIF ($3 = 2) THEN
        SELECT SUM(exchange_rate * amount) INTO adjustment
        FROM Employee_Adjustments
        WHERE (Employee_Month_ID = $1) AND (adjustment_type = $2) AND (In_payroll = true) AND (Visible = true);
    ELSIF ($3 = 3) THEN
        SELECT SUM(exchange_rate * amount) INTO adjustment
        FROM Employee_Adjustments
        WHERE (Employee_Month_ID = $1) AND (adjustment_type = $2) AND (In_Tax = true);

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