LINQ的加入where子句不工作

Question

我有这样的MSSQL的查询，我要转换为LINQ

select * from personas 
left join PersonaDocumento on PersonaDocumento.PersonaId=personas.Id 
where personas.FirstName='23895389' or PersonaDocumento.Documento='23895389' 

这不起作用：

from p in db.personas 
join d in db.PersonaDocumento on p.Id equals d.PersonaId into dj1 
where p.FirstName=='23895389' || dj1.Documento=='23895389' 
from d in dj1.DefaultIfEmpty() 
select p 

Answer 1

我想你了三次失误有：

from p in db.personas 
join d in db.PersonaDocumento on p.Id equals d.PersonaId into dj1 
where p.FirstName=='Jzuan' 
from d in dj1.DefaultIfEmpty() 
where d.Documento=='23895389' 
select d 

首先是join d on其中正确的语法是in。其次，您从p中选择，而不是从您加入的表格中选择d。 Plus dj1是一个元素列表，所以如果你需要过滤它中的元素，你应该在它之后做。具体表现在从d在dj1条款

Answer 2

尝试这样的：

from p in db.personas 
join d in db.PersonaDocumento on p.Id equals d.PersonaId into dj1 
from ld in dj1.DefaultIfEmpty() 
where p.FirstName=='Jzuan' || (ld != null && ld.Documento=='23895389') 
select p 

注意我是如何重新排序条款。