Database 相关的知识 - Update from/List down local files

1.Update from

--reference :http://stackoverflow.com/questions/2334712/update-from-select-using-sql-server

1) Sample 1

UPDATE foreignmidtidstaging

SET chsupdatestatus = 'N'

,errordescription = @ErrorMessage

FROM foreignmidtidstaging a

INNER JOIN terminalstaging b ON a.jobid = b.jobid

AND a.jobid = @JOBID

AND len(ISNULL(a.CHSUpdateStatus,''))=0

2)Sample 2

UPDATE [FOREIGNTERMINAL]

SET [ACQUIRERID] = @ACQUIRERID

,[MERCHANTID] = f.merchantid

,[lastUpdatedDate] = getdate()

FROM foreignMIDTIDStaging f

INNER JOIN terminalstaging t ON
T.jobid = f.jobid AND .....

AND f.Jobid = @JOBID

AND EXISTS (

SELECT 1

FROM foreignterminal ft

WHERE ft.acquirerid = @ACQUIRERID AND....

)

WHERE FOREIGNTERMINAL.acquirerid = @ACQUIRERID

AND FOREIGNTERMINAL.merchantid = f.merchantid AND....

NOTE : The where condition as above should not be skipped, otherwise the update maybe wrong.

2.List down local system files by using xp_cmdshell

CREATE TABLE ##SQLFiles ( SQLFileName VARCHAR(2000))

GO



INSERT INTO ##SQLFiles

EXECUTE master.dbo.xp_cmdshell 'dir /b "D:\DBScripts\20131002\*.sql"'

GO

DECLARE cFiles CURSOR LOCAL FOR

SELECT DISTINCT [SQLFileName]

FROM ##SQLFiles

WHERE [SQLFileName] IS NOT NULL AND

[SQLFileName] != 'NULL'

ORDER BY [SQLFileName]

DECLARE @vFileName VARCHAR(200)

DECLARE @vSQLStmt VARCHAR(4000)

OPEN cFiles

FETCH NEXT FROM cFiles INTO @vFileName

WHILE @@FETCH_STATUS = 0

BEGIN

PRINT ' @vFileName ' + @vFileName

FETCH NEXT FROM cFiles INTO @vFileName

END

CLOSE cFiles

DEALLOCATE cFiles

GO

DROP TABLE ##SQLFiles

GO