Question

基本上我有一个SQL Server 2008 R2数据库。该数据库有一个名为Node和Link的表。链接包含与节点中的Id相关的StartNodeId和EndNodeId。数据库还需要节点和链接之间的链接表，以便更快地检查说明，此节点是否与此链接相关或哪些节点与此链接相关。 Link表包含Identity密钥，NodeId和LinkId。我的问题是，当我正在进行插入操作时，我正在尝试使用合并语句，这些语句似乎无法完成我正在尝试的操作

当我尝试

时

MERGE INTO [RoadRoutingDatabase].[dbo].[NodeToLink] AS TARGET
USING (SELECT Id, StartNodeId, EndNodeId FROM [RoadRoutingDatabase].[dbo].[Link]) AS SOURCE
ON (TARGET.LinkId = SOURCE.Id)
WHEN MATCHED AND TARGET.NodeId = Source.StartNodeId THEN
    UPDATE SET TARGET.NodeId = SOURCE.StartNodeId,
               TARGET.LinkId = SOURCE.Id
WHEN MATCHED AND TARGET.NodeId = Source.EndNodeId THEN
    UPDATE SET TARGET.NodeId = SOURCE.EndNodeId,
               TARGET.LinkId = SOURCE.Id
WHEN NOT MATCHED BY TARGET AND TARGET.NodeId = Source.StartNodeId THEN
    INSERT (LinkId, NodeId)
    VALUES (SOURCE.Id, SOURCE.StartNodeId)
WHEN NOT MATCHED BY TARGET AND TARGET.NodeId = Source.EndNodeId THEN
    INSERT (LinkId, NodeId)
    VALUES (SOURCE.Id, SOURCE.EndNodeId)
WHEN NOT MATCHED BY SOURCE THEN
    DELETE;

我收到错误消息“类型为'WHEN MATCHED'的动作在MERGE语句的'UPDATE'子句中不能出现多次”

如果我尝试单独插入Start Nodes和End Nodes，例如

    --Insert Start Node To Link Relationships
    MERGE INTO [RoadRoutingDatabase].[dbo].[NodeToLink] AS TARGET
    USING (SELECT Id, StartNodeId FROM [RoadRoutingDatabase].[dbo].[Link]) AS SOURCE
    ON (TARGET.NodeId = SOURCE.StartNodeId AND TARGET.LinkId = SOURCE.Id)
    WHEN MATCHED THEN
        UPDATE SET TARGET.NodeId = SOURCE.StartNodeId,
                   TARGET.LinkId = SOURCE.Id
    WHEN NOT MATCHED BY TARGET THEN
        INSERT (LinkId, NodeId)
        VALUES (SOURCE.Id, SOURCE.StartNodeId)
    WHEN NOT MATCHED BY SOURCE THEN
        DELETE;

    --Insert End Node To Link Relationships
    MERGE INTO [RoadRoutingDatabase].[dbo].[NodeToLink] AS TARGET
    USING (SELECT Id, EndNodeId FROM [RoadRoutingDatabase].[dbo].[Link]) AS SOURCE
    ON (TARGET.NodeId = SOURCE.EndNodeId AND TARGET.LinkId = SOURCE.Id)
    WHEN MATCHED THEN
        UPDATE SET TARGET.NodeId = SOURCE.EndNodeId,
                   TARGET.LinkId = SOURCE.Id
    WHEN NOT MATCHED BY TARGET THEN
        INSERT (LinkId, NodeId)
        VALUES (SOURCE.Id, SOURCE.EndNodeId)
    WHEN NOT MATCHED BY SOURCE THEN
        DELETE;

我最终删除了链接（并不奇怪），所以基本上我想知道是否有人知道这样做的好方法？如果可能的话，我希望能够继续使用合并声明

由于

编辑：我找到了一种使用不同来源合并此数据的不同方法，问题现在已经解决了。

Answer 1

也许我错过了一些东西，但

错误消息抱怨您不能拥有多个WHEN MATCHED，因此您可以转换

WHEN MATCHED AND TARGET.NodeId = Source.StartNodeId THEN
    UPDATE SET TARGET.NodeId = SOURCE.StartNodeId,
               TARGET.LinkId = SOURCE.Id
WHEN MATCHED AND TARGET.NodeId = Source.EndNodeId THEN
    UPDATE SET TARGET.NodeId = SOURCE.EndNodeId,
               TARGET.LinkId = SOURCE.Id

到

WHEN MATCHED AND TARGET.NodeId IN (Source.StartNodeId,Source.EndNodeId) THEN
    UPDATE SET TARGET.NodeId = CASE 
                                 WHEN TARGET.NodeId = Source.StartNodeId 
                                 THEN SOURCE.StartNodeId 
                                 ELSE Source.EndNodeId 
                               END,
               TARGET.LinkId = SOURCE.Id

但是CASE的第一个分支在TARGET.NodeId = Source.StartNodeId时被点击并且还设置了TARGET.NodeId = Source.StartNodeId，并且类似于第二个分支，那么这似乎简化为

WHEN MATCHED AND TARGET.NodeId IN (Source.StartNodeId,Source.EndNodeId) THEN
    UPDATE SET TARGET.LinkId = SOURCE.Id

合并多个更新和插入

1 个答案: