I give this sql request:
$sql = "SELECT * FROM incoming_email order by 'status','serial' limit
1 ";

where status is a 5 char varchar and serial is a mediumint and the
primary key.

There is an index
STATUS with no cardinality and fields: status, serial

The row returned is the one with the lower serial, but a higher status

eg serial status
269 held
is returned instead of
270 (status is blank)

How should the selection be written ?

bill