SELECT M.userid,

userid is a field in table users not in msg. Try

SELECT SND.userid, SND.firstname, SND.lastname
FROM msg as M
JOIN users as SND 
  ON SND.userid = M.msg_from
WHERE M.msg_to = ? 
  AND M.received iS NULL

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poj

In reply to Re^5: output results from sql join by poj
in thread output results from sql join by bigup401

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