这是有问题的查询
return _projectDetail.ExpenditureDetails
.Where(detail => detail.ProgramFund == _programFund
&& detail.Expenditure.User == _creditCardHolder)
.Sum(detail => detail.ExpenditureAmounts.FirstOrDefault(
amount => amount.isCurrent && !amount.requiresAudit)
.CommittedMonthlyRecord.ProjectedEac);
表格结构
ProjectDetails(1对多)支出详细信息
支出细则(1比多)支出安装
ExpenditureAmounts(1对1)CommittedMonthlyRecords
ProjectedEac是CommittedMonthlyRecords上的十进制字段。
我在单元测试中发现的问题(尽管不太可能发生),以下行可能为空:
detail.ExpenditureAmounts.FirstOrDefault(
amount => amount.isCurrent && !amount.requiresAudit)
我的原始查询是一个嵌套循环,在那里我将多次访问数据库,我不想重复。我在这里看了一些类似的问题,但the solution didn't seem to fit。
有什么想法吗?
答案 0 :(得分:3)
为什么不检查null?
return _projectDetail.ExpenditureDetails.Where(detail =>
detail.ProgramFund == _programFund &&
detail.Expenditure.User == _creditCardHolder
).Sum(detail => {
var a = detail.ExpenditureAmounts.FirstOrDefault(
amount => amount.isCurrent && !amount.requiresAudit
);
return a != null ? a.CommittedMonthlyRecord.ProjectedEac : 0.0m;
});