I know this is old, but I needed a refresher and came across this. I've found it's better not to do the query in the sendmail. Export the file like this:

Execute xp_cmdshell 'SQLCMD -S VSQL2 -d urdatabase -U urname -P urpassword -Q "Select * from urfilename" -o C:\urexportedfile.csv -W -w 1500 -s","'

then just do the sendmail with an attachment- no query needed:

EXEC msdb.dbo.sp_send_dbmail

@profile_name = 'urSQLemailprofile',

@recipients = 'anyone@anywhere',

@subject = 'blah blah blah',

@body = 'more blah ',

@file_attachments= 'C:\urexportedfile.csv'

End

If your Windows Default Programs are set for Excel to open .csv files, it will open purty as you please.