根据给定年份的所有月份从一个表中选择记录，第二个表中的记录

Question

我在数据库中有两个表。

MembershipInstallments(ProjectId, AllotmentId, InstallmentId, EntryDate,AmountPaid)
Memberships(ProjectId, AllotmentId,ClientId,ClientName, RegistrationNo)

[我想选择客户在一年中按月支付的款项。还有那年开始之前支付的金额。我想要的结果集是

让我们说2019年

ClientName, RegistrationNumbers, PreviouslyPaidAmount(i-e all amount paid in 2018), AmountPaidInJuly 2019, AmountPaidInAugust2019. ..... AmountPaidIn Jun2020

EntryDate表中的MembershipInstallments是月份，>

我通过跟踪方法尝试过，但是对于大型数据集来说花费的时间太长。

        SELECT ClientName,RegistrationNo,
        (SELECT ISNULL(SUM(AmountPaid),0)
        FROM MembershipInstallments WHERE ProjectId=Membership.ProjectId AND 
        AllotmentId=Membership.AllotmentId AND EntryDate<@fromDate) ASPreviouslyPaid,
        (SELECT ISNULL (SUM(AmountPaid),0 FROM MembershipInstallments WHERE ProjectId=Membership.ProjectId 
        AND AllotmentId=Memberhsip.AllotmentId AND (MONTH(EntryDate) = 7) AND (YEAR(EntryDate) = 
        YEAR(@fromDate)) AS JulyPayment
        FROM Memberships WHERE ProjectId=@projectId
任何帮助将不胜感激。

我在数据库中有两个表。 MembershipInstallments（ProjectId，AllotmentId，InstallmentId，EntryDate，AmountPaid）Memberships（ProjectId，AllotmentId，ClientId，ClientName，RegistrationNo），我想...

Answer 1

Scalar子查询