摘要：
通过搜索论坛，我找到了三篇关于sum的文章http://www.codeisbug.com/Ask/9/4531http://www.codeisbug.com/Ask/14/4128文章1：我在2018年10月12日找到了一个解决方案。Sharevarquery=DB。FullClient。可查询<；合同订单、合同>；（（co，cs）=>；n
通过论坛的检索 查到三篇文章是关于sum的
http://www.codeisbug.com/Ask/9/4531
http://www.codeisbug.com/Ask/14/4128
文章1：
2018/10/12
我自己已经找到解决办法了,分享一下 var query = DB.FullClient.Queryable<ContractOrders, Contracts>((co, cs) => new object[]{ JoinType.Inner,co.ContractId==cs.Id }) .WhereIF(!string.IsNullOrEmpty(customerId), (co, cs) => cs.CustomerId == customerId) .WhereIF(startDate.HasValue, (co, cs) => cs.ActivateDate >= startDate.Value) .WhereIF(endDate.HasValue, (co, cs) => cs.ActivateDate <= endDate.Value.AddDays(1)) .WhereIF(status.HasValue, co => co.Status == status.Value) .Select((co, cs) => new ContractOrdersP<Contracts> { Code = co.Code, Id = co.Id, CreateTime = co.CreateTime, ContractId = co.ContractId, Remark = co.Remark, Status = co.Status, Contracts = cs, TotalPrice = SqlFunc.Subqueryable<ProductConfigs>() .Where(r => r.ContractOrderId == co.Id) .GroupBy(r => r.ContractOrderId) .Select(r => SqlFunc.AggregateSum(r.Quantity * r.DiscountPrice)) }); 用这个函数可以解决, SqlSugar作者 定义了AggregateSum 这种方法, 一般人还真不知道
文章2：
4.x .Max(it => it.id); .Sum(it => it.id);
官方文档的查询函数
SqlFunc.Subqueryable子查询的写法
//子查询的版本 var list = db.Queryable<TC020_Purchase>() .Select(a => new { guid = a.TC020_Guid, compony = a.TC020_Company, SignDate = a.TC020_SignDate, ProjectTitle = a.TC020_ProjectTitle, Signer = a.TC020_Signer, ContractID = a.TC020_ContractID, PaymentClaus = a.TC020_PaymentClause, TotalCount = a.TC020_TotalAmount, paid = SqlFunc.Subqueryable<TC022_PurchasePaymentRecord>() .Where(b => b.TC020_Guid == a.TC020_Guid) .Select(b => SqlFunc.AggregateSum(b.TC022_NotPaid.Value)).ToString(), notpaid = SqlFunc.Subqueryable<TC022_PurchasePaymentRecord>() .Where(b => b.TC020_Guid == a.TC020_Guid) .Select(b => SqlFunc.AggregateSum(b.TC022_Paid.Value)).ToString() }).ToList();
Group By的写法
//Group by 版本 var group = db.Queryable<TC020_Purchase, TC022_PurchasePaymentRecord>((a, b) => new object[] { JoinType.Left,a.TC020_Guid==b.TC020_Guid}) .GroupBy(a => new { a.TC020_Guid, a.TC020_Company, a.TC020_SignDate, a.TC020_ProjectTitle, a.TC020_Signer, a.TC020_ContractID, a.TC020_PaymentClause, a.TC020_SalesContractID, a.TC020_TotalAmount }) .Select((a,b)=> new { paid=SqlFunc.AggregateSum(b.TC022_NotPaid.Value).ToString(), notpaid= SqlFunc.AggregateSum(b.TC022_Paid.Value).ToString() }).ToList();