Sql 将两个select查询连接在一起

我需要合并两个select查询

  SELECT [DatapointID]
  ,[AssetID]
  ,[DatapointID]
  ,[SourceTag]
  ,'-' + [TimeStep] + [TimeStepValue] AS TimeStep
  ,[DataRetrievalInterval] + [DataRetrievalIntervalValue] AS [RetInterval]
  ,NULL AS DatapointDate
  ,NULL AS DatapointValue
  ,0 As DataFlagID
  ,DateADD(-1, d @SearchDateEnd) + @SearchTimeEnd DateDataGrabbed
  ,GetDate() DateTimeAddedtoDB
FROM [dbo].[tblTSS_Assets_Datapoints]
Where AssetID = 204     


Select DatapointDate, SUM(DataPointValue) as DataPointValue From @temp
GROUP BY DatapointDate
ORDER BY DatapointDate

第一个select查询是我想要的最终结果，而不是NULL，因为DatapointDate和DatapointValue是我想要的@temp中的值

---

如何执行此操作？

联接将组合两个表中的值。在这种情况下，没有明显的连接键，因此您将具有交叉连接：

SELECT [DatapointID], [AssetID], [DatapointID], [SourceTag],
       '-' + [TimeStep] + [TimeStepValue] AS TimeStep,
       [DataRetrievalInterval] + [DataRetrievalIntervalValue] AS [RetInterval],
       d.DatePointDate, d.DatapointValue,
       0 As DataFlagID,
       DateADD(-1, d @SearchDateEnd) + @SearchTimeEnd DateDataGrabbed,
       GetDate() DateTimeAddedtoDB
FROM [dbo].[tblTSS_Assets_Datapoints] cross join
     (Select DatapointDate, SUM(DataPointValue) as DataPointValue From @temp
      GROUP BY DatapointDate
     ) d
Where AssetID = 204  

但是，这将使行数相乘，每个日期一行。您有选择其中一行的特定规则吗