比较来自两个不同表的两行以获取更新的列

Question

I have two tables, one history and one actual

HistoryTable

ActualCalcID DSID        FormatID    RollupId    BD                                       BID         DFID        FMID        Year        Name                                     TID         SID         TyId
------------ ----------- ----------- ----------- ---------------------------------------- ----------- ----------- ----------- ----------- ---------------------------------------- ----------- ----------- -----------
18           40          3           1           Test Edit VB                             2           1           1           2016        CCG Contribution Margin (000s) - Test    4           101         3
18           40          3           1           Test Edit VB1                            2           1           1           2016        CCG Contribution Margin (000s) - Test1   4           101         3

ActualTable

ActualCalcID DSID        FormatID    RollupId    BD                                       BID         DFID        FMID        Year        Name                                     TID         SID         TyId
------------ ----------- ----------- ----------- ---------------------------------------- ----------- ----------- ----------- ----------- ---------------------------------------- ----------- ----------- -----------
18           40          4           2           Test Edit VB2                            2           1           2           2016        CCG Contribution Margin (000s) - Test2   5           101         5

When user clicks on a button in UI, the row from ActualTable is moved to HistoryTable with the help of an trigger (basically Archiving).

I need which columns have changed when the trigger run completed, in below format

Changed Field | Changed Field Content

FormatId | 3

Rollup Id | 2

BD | Test Edit VB1

FMID | 2

Name | CCG Contribution Margin (000s) - Test1

TID | 5

TypeId | 5

I think I did not ask my question properly. I want to compare the latest row from history table and the row from actual tables to check which columns have changed. It might be different at different times, some times there will be 4 column changed, sometimes 5, sometimes 1. the output table needs to be logged with only entry for changed column.

Answer 1

You can use UNION ALL :

SELECT 'FormatId' AS [Changed Field], CONVERT(VARCHAR(100), FormatId) AS [Changed Field Content] FROM Actual UNION ALL
SELECT 'Rollup Id', CONVERT(VARCHAR(100), RollupId) FROM Actual UNION ALL
SELECT 'BD', CONVERT(VARCHAR(100), BD) FROM Actual UNION ALL
SELECT 'FMID', CONVERT(VARCHAR(100), FMID) FROM Actual UNION ALL
SELECT 'Name', CONVERT(VARCHAR(100), Name) FROM Actual UNION ALL
SELECT 'TID', CONVERT(VARCHAR(100), TID) FROM Actual UNION ALL
SELECT 'TypeId', CONVERT(VARCHAR(100), TID) FROM Actual

Answer 2

Use Table valued constructor with cross apply to unpivot the data

select [Changed Field] , [Changed Field Content]
from yourtable
cross apply
(
values ('FormatId',CONVERT(VARCHAR(100), FormatId)),
(Rollup Id', CONVERT(VARCHAR(100), RollupId)),
('BD', CONVERT(VARCHAR(100), BD)),
('FMID', CONVERT(VARCHAR(100), FMID)),
('Name', CONVERT(VARCHAR(100), Name)),
('TID', CONVERT(VARCHAR(100), TID)),
('TypeId', CONVERT(VARCHAR(100), TID))
) 
cs ([Changed Field] , [Changed Field Content])

Answer 3

You can use OUTPUT after your INSERT to get the inserted row. You need to apply this in your trigger.

DECLARE @TableVar TABLE(
    ChangedField VARCHAR(50)                       
    ,FormatId INT
    ,RollupId INT
    ,BD VARCHAR(50)
    ,FMID INT
    ,Name VARCHAR(250)
    ,TID INT
    ,TypeId INT
)

INSERT HistoryTable
    OUTPUT 'Changed Field Content'
            ,inserted.FormatId
            ,inserted.RollupId
            ,inserted.BD
            ,inserted.FMID
            ,inserted.Name
            ,inserted.TID
            ,inserted.TypeId
        INTO @TableVar
VALUES ('', '', ...)

SELECT * FROM @TableVar