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Question

如何才能完成。 sql是用Linq编写的。我正在使用LinqToEntities，C＃。 @companyID＆amp; @branchID是参数

select * from tblEmp e
where e.deleted = 0 and
(e.companyId = @companyID OR e.companyid is null) and
(e.branchId = @branchID OR e.branchid is null)

目前，存在相同的存储过程，我在linq中使用它，如下所示：

var qry = from d in MYDB.GetData(int companyid, int branchid)
select new
{
//all reqd. columns...
}

所以，是否可以直接在Linq中编写上述内容。

修改

public IEnumerable<tblEmp> GetData(Guid gCID, Guid gBID)
{
  var employees = (from e in tblEmp
                 where !e.deleted
                 && (e.companyId == gCID || e.companyid == null)
                 && (e.branchId == gBID || e.branchid == null)
                 select e
                 ).AsEnumerable();
}

//两个参数都是'00000000-0000-0000-0000-000000000000'。我期待所有的记录，但计数是0.我哪里错了。

Answer 1

不确定

var employees = (from e in tblEmp
                 where !e.deleted
                 && (e.companyId == aCompanyIdHere || e.companyid == null)
                 && (e.branchId == aBranchIdHere || e.branchid == null)
                 select new
                 {
                     e.Id,
                     e.companyId,
                     e.branchId
                 });

修改

查询应该有效，但我怀疑你的要求有点不同。如果您希望在传入参数Guid为空时获取所有项目，则可以执行以下操作。

public IEnumerable<tblEmp> GetData(Guid gCID, Guid gBID)
{
    var employees = (from e in tblEmp
                     where !e.deleted
                     && (gCID == Guid.Empty || e.companyid == gCID)
                     && (gBID == Guid.Empty || e.branchid == gBID)
                     select e
                     ).AsEnumerable();
}

但为了更好的可读性，IMO：

public IEnumerable<tblEmp> GetData(Guid? gCID, Guid? gBID)
{
    var employees = (from e in tblEmp
                     where !e.deleted
                     && (gCID == null || e.companyid == gCID)
                     && (gBID == null || e.branchid == gBID)
                     select e
                     ).AsEnumerable();
}

如果您想要所有记录，请传入null而不是Guid.Empty。

var data = GetData(null, null);

Answer 2

var qry = (
    from test in MYDB.tblEmp
    where !e.deleted
        && (e.companyId == "any id" || e.companyid == null)
        && (e.branchId == "anyid" || e.branchid == null)
    select test
).FirstOrDefault();

linq与null条件

2 个答案:

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