通过值加入两个表

Question

我想通过第2个表的值来链接2个表。

我有2张桌子。 case_activity（主记录表）和case_activity_changes（日志表）。这两个表是通过ActivityId链接的。

我的第一张桌子看起来像这样

SELECT activityid, caseId, description FROM dbo.case_activity WHERE CaseId = 35057152

activityid  caseId      description
----------- ----------- --------------------------------------------------
229098      35057152    Receive data correction request from participant
229099      35057152    Verify proof of change, if applicable
229100      35057152    Update Data
229101      35057152    Review / Update pension check address, if app
229102      35057152    Review/Update pension state tax elections, if app
229103      35057152    Technical Review
229104      35057152    Send to print
229105      35057152    Send data change to trustee, if app
229106      35057152    First Call Attempt
229107      35057152    Send data change to NQ pension payer, if app

和第二个

SELECT  * FROM dbo.case_activity_changes WHERE ActivityId = 229189

ActivityId  TransactionId fieldname                                          OldValue
----------- ------------- -------------------------------------------------- ----------------------------
229189      32710860      ** INSERTED **                                     NULL
229189      32710861      TransactionId                                      32710860
229189      32710861      ViewByAssigned                                     NULL
229189      32710862      ** DELETED **                                      NULL
229189      32710862      ActivityId                                         229189
229189      32710862      AssignedDate                                       Jan 16 2020  6:47AM
229189      32710862      AssignedUserId                                     51809
229189      32710862      BeginDate                                          NULL
229189      32710862      CaseId                                             35057152
229189      32710862      ChangedUserId                                      51809
229189      32710862      CompletedDate                                      NULL
229189      32710862      CompletedUserId                                    NULL
229189      32710862      CreatedDate                                        Jan 16 2020  6:47AM
229189      32710862      CreatedUserId                                      51809
229189      32710862      Description                                        DO
229189      32710862      DueDate                                            NULL
229189      32710862      EmailSentTo                                        NULL
229189      32710862      NoteText                                           NULL
229189      32710862      SequenceOrder                                      40
229189      32710862      Status                                             1
229189      32710862      SubtypeId                                          341
229189      32710862      TransactionId                                      32710861
229189      32710862      ViewedByAssigned                                   Jan 16 2020  6:47AM

我的结果应该看起来像这样

activityid  caseId      description                                          action
----------- ----------- -------------------------------------------------------------
229098      35057152    Receive data correction request from participant
229099      35057152    Verify proof of change, if applicable
229100      35057152    Update Data
229101      35057152    Review / Update pension check address, if app
229102      35057152    Review/Update pension state tax elections, if app
229103      35057152    Technical Review
229104      35057152    Send to print
229105      35057152    Send data change to trustee, if app
229106      35057152    First Call Attempt
229107      35057152    Send data change to NQ pension payer, if app
229189      35057152    DO                                                  DELETED

请注意，最后一条记录activityid = 229189在case_activity中不再存在，但是有一个登录case_activity_changes，指示其已删除，描述值为“ DO”，caseId = 35057152

Answer 1

您无需为此使用join。对于已删除的交易，请使用union。

select activityid, caseId, description, '' as Action
from dbo.case_activity  where CaseId = 35057152
union all
select ActivityId, 35057152, 'Do', 'Deleted'
from bo.case_activity_changes where ActivityId not in 
    (select activityid from dbo.case_activity where CaseId = 35057152)