If the Notes and RFC822 fields are in a Blob format where their values are not standard text use this:
Select
c.USERID, c.ACCOUNTNO, c.RECTYPE, c.ONDATE, c.[ONTIME], c.[DURATION], c.REF as [Subject History - REF],
c.LINKRECID, c.recid,
CAST(CAST(c.NOTES AS varbinary(4000)) AS varchar(4000)) AS NOTES,
CAST(CAST(m.RFC822 AS varbinary(4000)) AS varchar(4000)) AS RFC822
From CAL as c
Left Join MAILBOX as m
ON c.LINKRECID = m.recid
If the Notes and RFC822 fields are in a standard text format you can use this query:
set textsize 4000
Select
c.USERID, c.ACCOUNTNO, c.RECTYPE, c.ONDATE, c.[ONTIME], c.[DURATION], c.REF as [Subject History - REF],
c.LINKRECID, c.recid, c.NOTES, m.RFC822
From CAL as c
Left Join MAILBOX as m
ON c.LINKRECID = m.recid