如何比较 SQL Server 中的两个表 [关闭]

Question

我需要比较 SQL Server 中的两个表，如下所示，我需要比较两列。

表1

SystemName, ReconID

hostname1,Recon1
hostname2,Recon2
hostname7,Recon3

表2

AssetName, ReconID

hostname1,Recon1
hostname2,Recon6
hostname3,Recon3

比较条件：

1. SystemName = AssetName AND ReconID ReconID
2. SystemName AssetName AND ReconID = ReconID
3. SystemName = AssetName AND ReconID = ReconID

请帮助我处理 SQL 查询。 我已经尝试过以下事情。

Answer 1

如果你想查看数据，那么你可以这样做：

select "Condition 1" as condition
     , SystemName
     , AssetName
     , Table1.ReconID as "Table1_ReconID"
     , Table2.ReconID as "Table2_ReconID"
from Table1, Table2
where SystemName = AssetName AND Table1.ReconID <> Table2.ReconID
union 
select "Condition 2" as condition
     , SystemName
     , AssetName
     , Table1.ReconID as "Table1_ReconID"
     , Table2.ReconID as "Table2_ReconID"
from Table1, Table2
where SystemName <> AssetName AND Table1.ReconID = Table2.ReconID
union
select "Condition 3" as condition
     , SystemName
     , AssetName
     , Table1.ReconID as "Table1_ReconID"
     , Table2.ReconID as "Table2_ReconID"
from Table1, Table2
where SystemName = AssetName AND Table1.ReconID = Table2.ReconID
order by condition

在相交的情况下，使用“union all”而不是“union”。