如何在merge语句的`when`子句中使用条件？

Question

我有两个表，并希望插入或更新从tableA到TableB chages。

PatientId和ComposeId两个表

table A 
PatientId 
ComposeId 
Name 
Family 

table B 
PatientId 
ComposeId 
Name 
Family 

我想要实现这样的事情，或者可能使用嵌套合并的复合键。怎么做？

Merge TbleB as Target 
using (select PatientId,Compseid,Name,Family from TableA) as source 
on (source.PatientId=target.PatientId and source.ComposeId=target.Composeid and source.Name=Target.Name 
and Source.Family=target.Family) 
when not matched and source.patientId=target.PatientId and Source.CompositionId=Target.CompistionId 
    then update 
     set Name=Source.Name, 
     set Family=Source.Family 
when not matched and (source.patientId<>target.PatientId and Source.CompositionId<>Target.CompistionId) then 
    Insert 

Answer 1

我认为您在ON条款中放置了太多条件。我觉得你只是想：

Merge TbleB as Target 
using (select PatientId,Compseid,Name,Family from TableA) as source 
on source.PatientId=target.PatientId and source.ComposeId=target.Composeid 
when matched --You could add the Name<>Name or Family<>Family WHEN condition here 
      --if wanted, but I wouldn't bother usually 
    then update 
     set Name=Source.Name, 
     set Family=Source.Family 
when not matched then 
    Insert 

只是想指出，以下不作任何意义：

when not matched and source.patientId=target.PatientId and Source.CompositionId=Target.CompistionId 

when not matched是说，有没有排在target相匹配的要求，在您的ON条款中指定。因此，在这里的附加条件中对target的任何引用都不可能起作用。