1

我有这个 linq 查询：

(from  rapportBase in New_RapportReferencementBases
join rapportExtensionAll in New_RapportReferencementExtensionBases on rapportBase.New_RapportReferencementId equals rapportExtensionAll.New_RapportReferencementId into jointureRapportExtension
from rapportExtension in jointureRapportExtension.DefaultIfEmpty()

join packExtensionAll in New_PackExtensionBases on rapportExtension.New_PackId equals packExtensionAll.New_PackId into jointurePackExtension
from packExtension in jointurePackExtension.DefaultIfEmpty()
join packBaseAll in New_PackBases on packExtension.New_PackId equals packBaseAll.New_PackId into jointurePackBase
from packBase in jointurePackBase.DefaultIfEmpty()

join domaineBaseAll in New_DomaineBases on packExtension.New_DomaineId equals domaineBaseAll.New_DomaineId into jointureDomaineBase
from domaineBase in jointureDomaineBase.DefaultIfEmpty()
join domaineExtensionAll in New_DomaineExtensionBases on domaineBase.New_DomaineId equals domaineExtensionAll.New_DomaineId into jointureDomaineExtension
from domaineExtension in jointureDomaineExtension.DefaultIfEmpty()  

join compteBaseAll in AccountBases on domaineExtension.New_AccountId equals compteBaseAll.AccountId into jointureCompteBase
from compteBase in jointureCompteBase.DefaultIfEmpty()
join compteExtensionAll in AccountExtensionBases on compteBase.AccountId equals compteExtensionAll.AccountId into jointureCompteExtension
from compteExtension in jointureCompteExtension.DefaultIfEmpty()   
select rapportBase)

生成：

SELECT [t0].[New_RapportReferencementId], [t0].[CreatedOn], [t0].[CreatedBy], [t0].[ModifiedOn], [t0].[ModifiedBy], [t0].[OwningUser], [t0].[OwningBusinessUnit], [t0].[statecode] AS [Statecode], [t0].[statuscode] AS [Statuscode], [t0].[DeletionStateCode], [t0].[VersionNumber], [t0].[ImportSequenceNumber], [t0].[OverriddenCreatedOn], [t0].[TimeZoneRuleVersionNumber], [t0].[UTCConversionTimeZoneCode]
FROM [New_RapportReferencementBase] AS [t0]
LEFT OUTER JOIN [New_RapportReferencementExtensionBase] AS [t1] ON [t0].[New_RapportReferencementId] = [t1].[New_RapportReferencementId]
LEFT OUTER JOIN [New_PackExtensionBase] AS [t2] ON [t1].[New_PackId] = ([t2].[New_PackId])
LEFT OUTER JOIN [New_PackBase] AS [t3] ON [t2].[New_PackId] = [t3].[New_PackId]
LEFT OUTER JOIN [New_DomaineBase] AS [t4] ON [t2].[New_DomaineId] = ([t4].[New_DomaineId])
LEFT OUTER JOIN [New_DomaineExtensionBase] AS [t5] ON [t4].[New_DomaineId] = [t5].[New_DomaineId]
LEFT OUTER JOIN [AccountBase] AS [t6] ON [t5].[New_AccountId] = ([t6].[AccountId])
LEFT OUTER JOIN [AccountExtensionBase] AS [t7] ON [t6].[AccountId] = [t7].[AccountId]

但我想生成：

SELECT [t0].[New_RapportReferencementId], [t0].[CreatedOn], [t0].[CreatedBy], [t0].[ModifiedOn], [t0].[ModifiedBy], [t0].[OwningUser], [t0].[OwningBusinessUnit], [t0].[statecode] AS [Statecode], [t0].[statuscode] AS [Statuscode], [t0].[DeletionStateCode], [t0].[VersionNumber], [t0].[ImportSequenceNumber], [t0].[OverriddenCreatedOn], [t0].[TimeZoneRuleVersionNumber], [t0].[UTCConversionTimeZoneCode]
FROM [New_RapportReferencementBase] AS [t0]
FULL OUTER JOIN [New_RapportReferencementExtensionBase] AS [t1] ON [t0].[New_RapportReferencementId] = [t1].[New_RapportReferencementId]
FULL OUTER JOIN [New_PackExtensionBase] AS [t2] ON [t1].[New_PackId] = ([t2].[New_PackId])
FULL OUTER JOIN [New_PackBase] AS [t3] ON [t2].[New_PackId] = [t3].[New_PackId]
FULL OUTER JOIN [New_DomaineBase] AS [t4] ON [t2].[New_DomaineId] = ([t4].[New_DomaineId])
FULL OUTER JOIN [New_DomaineExtensionBase] AS [t5] ON [t4].[New_DomaineId] = [t5].[New_DomaineId]
FULL OUTER JOIN [AccountBase] AS [t6] ON [t5].[New_AccountId] = ([t6].[AccountId])
FULL OUTER JOIN [AccountExtensionBase] AS [t7] ON [t6].[AccountId] = [t7].[AccountId]

换句话说，我想为此查询生成完整的外部联接，而不仅仅是离开。

有人知道如何以简单的方式做到这一点吗？

谢谢

4

3 回答 3

1

Linq 中没有完全外部联接。你必须做两个左连接并将它们连接在一起。这是一些看起来像 linq 的伪代码：

var foj =
    (from l in left
    join r in right on l.Id equals r.Id into g
    from r in g.DefaultIfEmpty()
    select new { l, r })
    .Concat
    (from r in right
    join l in left on r.Id equals l.Id into g
    from l in g.DefaultIfEmpty()
    where l == null
    select new { l, r });

如果您打算使用 Linq to Sql，最好将此逻辑推送到存储过程中。

于 2009-09-14T14:09:44.607 回答
0

请参阅 VB 团队的这篇文章：

http://blogs.msdn.com/vbteam/archive/2008/02/12/converting-sql-to-linq-part-9-full-outer-join-bill-horst.aspx

看起来有点啰嗦。

否则，可能有一种方法可以使用外键和联合运算符来实现您想要的。

于 2009-09-14T14:02:24.183 回答
0

可悲的是，我以前看到过，但我想确定一下。

我们所做的事情是在存储过程中执行它并通过 linqtosql 方法访问它。

然后我们映射表结果，就像 linqtosql 做的那样，使用分组来获取链接到另一个实体的实体集合。

例如，如果我们有一个包含一些联系人链接的帐户。我们要求他们每个人的所有联系人都具有完全加入的帐户，并且他们按帐户 ID 分组以获取每个联系人的列表。

它工作得很好，但如果 linqtosql 能够生成完全连接会更好......

于 2009-09-22T09:31:46.807 回答