我无法执行下面的 linq。
var items( from p in Patients
join q in MURWorksheets on p.PatientId equals q.PatientId into step1
from s in step1.DefaultIfEmpty()
join t in MURWorksheetAnswers on s.MURWorksheetId equals t.MURWorksheetId into step2
from s2 in step2.DefaultIfEmpty()
select new {p.FirstName , Date = (s.MURDate == null ? DateTime.Now.Date : s.MURDate),
s2.MURQuestionnaireId,s2.MURExpctedAnswersId}).ToList();
这里是同样的sql,供大家引用。
select a.FirstName,b.MURDate,c.MURQuestionnaireId,c.MURWorksheetAnswersID from Patients as a
left join MURWorksheet as b on a.PatientId = b.PatientId
left join MURWorksheetAnswers as c on b.MURWorksheetId = c.MURWorksheetId
最佳答案
您粘贴的代码中缺少等号:
var items = (from p in Patients
join q in MURWorksheets on p.PatientId equals q.PatientId into step1
from s in step1.DefaultIfEmpty()
join t in MURWorksheetAnswers on s.MURWorksheetId equals t.MURWorksheetId into step2
from s2 in step2.DefaultIfEmpty()
select new {p.FirstName , Date = (s.MURDate == null ? DateTime.Now.Date : s.MURDate),
s2.MURQuestionnaireId,s2.MURExpctedAnswersId}).ToList();
关于Linq表达式多重左外连接错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/18360908/