Question

我已经用Google搜索了我最新的LINQ努力的例子（“嗨，我是LINQ的新手”）。我会把你去过的页面列表留给你。

以下是我想要实现的SQL示例：

use myDB;
go

declare @requestedDay datetime = convert(datetime, (convert(varchar(10), getdate(), 101)), 101)
declare @type1 int = 20

;with currentQuery as ( select
case when z.someID = @type1 and bet.someValue is null then 1
    else 0 end as count1,
case when z.someID = @type1 and bet.someValue = alef.otherID then 1
    else 0 end as count2,
from dbo.Work as dalet
    left join dbo.Workers as z on alef.workerAssignedID = z.ID
    left join dbo.Contracts as alef on alef.workOrderID = gimel.ID
    left join dbo.Subcontracts as bet on alef.WorkOrderID = alef.WorkOrderID 
                  and alef.WorkerAssignedID = dalet.WorkerID 
where convert(varchar(10),alef.dateTimeofWork,101) = @requestedDay),
futureQuery as ( select
case when gimel.text_EN like '%blah%' and bet.someValue is null then 1
    else 0 end as count3,
case z.someID = @type1 and bet.someValue = alef.otherID then 1
    else 0 end as count4,
from dbo.Work as dalet
    left join dbo.Workers as z on dalet.workerAssignedID = z.ID
    left join dbo.Contracts as alef on dalet.workOrderID = alef.ID
    left join dbo.Subcontracts as bet on dalet.WorkOrderID = bet.WorkOrderID and wa.WorkerAssignedID = wr.WorkerID 
    left join dbo.Lookups as gimel on dalet.skillID = gimel.ID
where convert(datetime,(convert(varchar(10),alef.dateTimeofWork,101)),101) > @requestedDay)
select sum(count1) as prop1name, sum(count2) as prop2name, 
sum(count3) as prop3name, sum(count4) as prop4name
from currentQuery, futureQuery

这当然是一个更大的查询的缩短版本。它只包含我需要的基础知识。名字可能令人困惑，但我一直在寻找独特的东西。他们也匹配下面的LINQ表兄弟。

...说，这就是我被困住的地方:(“我到目前为止所尝试的内容：”）我已经包含了一些描述我试图思考的问题的评论。

//snip injection stuff above
    public IQueryable<DailyCasaLatinaReport> DailyCasaLatina(DateTime dateRequested)
    {
        IQueryable<DailyCasaLatinaReport> query;

        var daletQ = waRepo.GetAllQ();
        var zQ = zRepo.GetAllQ();
        var alefQ = alefRepo.GetAllQ();
        var betQ = betRepo.GetAllQ();
        var gimelQ = gimelRepo.GetAllQ();

        int type1 = 20;
        int type2 = 21;

        query = daletQ
                   .GroupJoin(gimelQ, dalet => dalet.skillID, look => look.ID,
                                 (dalet, look) => new
                                 {
                                     dalet,
                                     enSkillText = look.FirstOrDefault().text_EN
                                 }) //currently envisioning a left outer join of
                                    //all .skillID, with English text available
                                    //for column and condition matches from the
                                    //next three joins.
                   .GroupJoin(betQ, gimel => gimel.dalet.workOrderID, wr => wr.WorkOrderID,
                                  (gimel, wr) => new
                                  {
                                      gimel,
                                      reqWorkerID = wr.FirstOrDefault().WorkerID,
                                      reqOrderID = wr.FirstOrDefault().WorkOrderID
                                  }) //now envisioning a join on the original table
                                     //where any match in workerID is joined. THIS
                                     //IS A PROBLEM, I actually need to join on two
                                     //conditions to avoid duplicates.
                   .GroupJoin(alefQ, bet => bet.gimel.dalet.workOrderID, wo => wo.ID,
                                  (bet, wo) => new
                                  {
                                      bet,
                                      timeOfWork = wo.FirstOrDefault().dateTimeofWork
                                  }) //now envisioning yet another join where the
                                     //dateTimeofWork property from woQ is stamped
                                     //onto all matches of woQ's ID column. since
                                     //woQ.ID is the common point of reference for
                                     //like, everything, there should be no nulls.
                   .GroupJoin(zQ, alef => alef.bet.gimel.dalet.workerAssignedID, w => w.ID,
                                 (alef, w) => new
                                {
                                    alef,
                                    listDWC = alef.bet.someValue == 0 ? (w.FirstOrDefault().someID == type1 ? 1 : 0) : 0,
                                    propioDWC = alef.bet.someValue == alef.bet.gimel.dalet.workerAssignedID ? 
                                                    (w.FirstOrDefault().someID == type1 ? 1 : 0) : 0,

                                })  
                                    // here I'm stuck because there's no way to do 
                                    //the future conditions, i.e., what would be my 
                                    //second subquery
                   .Where(x => x.alef.timeOfWork == dateRequested)
                   .GroupBy(y => y.alef.bet.gimel.dalet.ID)
                   .Select(group => new dailyReport
                                {
                                    count1 = group.Sum(z => z.listDWC),
                                    count2 = group.Sum(z => z.propioDWC),
                                    count3 = //???
                                    count4 = //???
                                });

        return query;
    }
//snip class definition below

所以，抱歉这个长期的问题（尽管我已经看过更久了），但是关于如何在这里挤压我的第二个子查询的任何想法都会有所帮助。我不知道LINQ那个老实说不知道我是否可以单独放置.Where子句和/或第二个.Select子句。需要注意的一点是dailyReport是一个已定义的类，必须具有（在我们的示例中）count1 thru count4。

感谢任何帮助，

哈伊姆

Answer 1

根据评论确定，破解这个怪物sql查询会更有利于他的代码的可维护性，如果需要，还会创建一个新问题。

LINQ to Entities扩展;多个子查询，连接和case语句

1 个答案: