How can I BCP queryout with filename from table? - sql

Question

I'm extracting many BLOBs to files using BCP and wonder if there's a way to give each file a unique name using an ID field from the SQL table.
This works:
DECLARE #Command NVARCHAR(4000)
SET #Command = 'bcp "SELECT FileData FROM MyDB.dbo.Attachments
WHERE Hist_ID = ''00004F13''"
queryout "C:\Wha.pdf" -T -c -C RAW -S SERVERNAME -U SA -P pa$$word'
EXEC xp_cmdshell #Command
But to get the filename, I've tried:
DECLARE #FileName varchar(50),
#Command NVARCHAR(4000)
SET #FileName = Hist_ID+'wha.PDF'
SET #Command = 'bcp "SELECT FileData FROM MyDB.dbo.Attachments
WHERE Hist_ID = ''00004F13''" queryout'
SET #Command = #Command + 'C:\' + #FileName + '-T -c -C RAW
-S SERVERNAME -U SA -P pa$$word'
EXEC xp_cmdshell #Command
I get an error: Invalid column name 'Hist_ID'.
Is there some way to do this? Thanks for any help!

Answer 1

Try this. This is the only way I know have to execute one row at a time.
This code just prints the command. Uncomment the xp_cmdshell to make it actually run. You might want to start with a small sample first (by limiting the select)
DECLARE #Hist_ID VARCHAR(100)
DECLARE #Ext VARCHAR(10)
DECLARE #Command NVARCHAR(4000)
DECLARE cAttachments CURSOR FOR
SELECT DISTINCT Hist_ID,Extension
FROM MyDB.dbo.Attachments
ORDER BY Hist_ID
OPEN cAttachments
FETCH NEXT FROM cAttachments
INTO #Hist_ID, #Ext
WHILE ##FETCH_STATUS = 0
BEGIN
SET #Command = 'bcp "SELECT FileData FROM MyDB.dbo.Attachments
WHERE Hist_ID = ''' + #Hist_ID + '''"
queryout "C:\' + #Hist_ID + '.' + #Ext + '" -T -c -C RAW -S SERVERNAME -U SA -P pa$$word'
PRINT #Command
-- EXEC xp_cmdshell #Command
FETCH NEXT FROM cAttachments
INTO #Hist_ID, #Ext
END
CLOSE cAttachments
DEALLOCATE cAttachments