Question

我有两张桌子 PatientEncounterDemo和PatientMaster

PatientEncounterDemo：

PateientID(F.K int),
DoctorId( F.K int),
ProcedureName



PatientMaster:

PatientId(P.K identity)
PatientFirstName(varchar(50)),
PatientLastName(varchar(50)),
PatientDOB

我需要提取PatientName（patientFirstName_ + patientLastName），patientDOB和分配给特定患者的程序计数（患者可以分配许多程序）

我为该结果编写了SQL查询：

//This puts the join inside count-

select distinct  PatientFirstName+ ' ' + PatientLastName as PatientName,PatientDOB,COUNT(ProcedureName) as [Proc Count] from
(
select distinct  p.PatientFirstName,p.PatientLastName,p.PatientDOB,e.ProcedureName
from PatientMaster p,PatientEncounterDemo e 
where p.PatientId=e.PatientId and e.DoctorId=1
)as mytable group by PatientFirstName,PatientLastName,PatientDOB

但是，我正在努力通过linq查询来做到这一点。请建议某种方式.. !!

Answer 1

这将是从SQL到LINQ的（几乎）一对一映射：

var myTable = (
    from encounter in db.PatientEncounterDemos
    where encounter.Doctor.Id == 1
    let patient = encounter.Patient
    select    new 
    {
        patient.FirstName, 
        patient.LastName,         
        patient.DOB,
        encounter.ProcedureName
    })
    .Distinct();

var results =
    from item in myTable
    group item by new { item.FirstName, item.LastName, item.DOB } into g
    select new 
    { 
        PatientName = g.Key.FirstName + " " + g.Key.LastName, 
        g.Key.DOB, 
        ProcCount = g.Count() 
    };

但这会更容易理解：

var myTable = (
    from encounter in db.PatientEncounterDemos
    where encounter.Doctor.Id == 1
    select new { encounter.Patient, encounter.ProcedureName })
    .Distinct();

var results =
    from item in myTable
    group item by item into g
    select new 
    { 
        PatientName =
            g.Key.Patient.FirstName + " " + g.Key.Patient.LastName, 
        g.Key.DOB, 
        ProcCount = g.Count() 
    };

Answer 2

希望这可以实现你的目标：

var patientProcedureCounts =
    from master in PatientMasters
    select new
    {
        master.PatientId,
        PatientName = master.PatientFirstName + " " +
            master.PatientLastName,
        master.PatientDOB,
        ProcedureCount = (from demo in PatientEncounterDemos 
            where demo.PatientId == master.PatientId &&
                demo.DoctorId == 1 
            select 1).Count()
    };

这将选择所有PatientMasters，然后为PatientEncounterDemos和PatientId选择所有DoctorId。最后，它将使用主要细节和该患者的演示计数来构建一个新的匿名类型，可以这样枚举：

foreach(var procedureInfo in patientProcedureCounts)
{
    Console.WriteLine("Patient {0} born on {1} had {2} procedures", 
        procedureInfo.PatientName, procedureInfo.PatientDOB, procedureInfo.ProcedureCount);
}

以下是LINQPad生成的SQL，它看起来非常接近您的目标：

-- Region Parameters
DECLARE @p0 NVarChar(1000) SET @p0 = ' '
DECLARE @p1 Int SET @p1 = 1
-- EndRegion
SELECT [t0].[PatientId], ([t0].[PatientFirstName] + @p0) + [t0].[PatientLastName] AS [PatientName], [t0].[PatientDOB], (
    SELECT COUNT(*)
    FROM [PatientEncounterDemo] AS [t1]
    WHERE ([t1].[PatientId] = [t0].[PatientId]) AND ([t1].[DoctorId] = @p1)
    ) AS [ProcedureCount]
FROM [PatientMaster] AS [t0]

Answer 3

我已经重写了你的SQL（希望能够工作）。这应该更容易从中生成LINQ。

SELECT 
    p.PatientFirstName + ' ' + p.PatientLastName as PatientName
    p.PatientDOB,
    COUNT(e.ProcudureName) AS [Proc Count]
FROM 
    PatientMaster p
    INNER JOIN PatientEncounterDemo e ON p.PatientId = e.PatientId
WHERE
    e.DoctorId=1
GROUP BY
    p.PatientFirstName,
    p.PatientLastName,
    p.PatientDOB

Answer 4

最后，在你所有答案的支持下，我得到了这个查询的确切结果。

首先，我执行了内连接以及db上的where条件。

然后，我按照多个列对结果进行分组，并对该组执行计数。

我的Linq查询：

 var myTable = (
          from master in MyDataContext.PatientMasters
          join encounter in MyDataContext.PatientEncounterDemos
          on master.PatientId equals encounter.PatientId
          where encounter.DoctorId == doctorID
          select new { master.PatientFirstName, master.PatientLastName, master.PatientDOB, encounter.ProcedureName })
          .Distinct();

      var results =
          from item in myTable
          group item by new { item.PatientFirstName, item.PatientLastName, item.PatientDOB } into grp
          select new
          {
              PatientName =
                  grp.Key.PatientFirstName + " " + grp.Key.PatientLastName,
              grp.Key.PatientDOB,
              ProcCount = grp.Count()
          };

现在我应用Foreach循环将结果导入列表.. !! 感谢所有...... !!!!

Linq查询计数外连接

4 个答案: