you need to use 2 recodsets
one to look up the previous record, the other to lookup the next record.
rsPrevious:
SELECT * FROM tableName WHERE idColumn < paramID ORDER BY idColumn DESC LIMIT 1
Variables:
Name: idColumn
type: Integer
Default Value: -1
Runtime value: $_GET['itemid']
rsNext
SELECT * FROM tableName WHERE idColumn > paramID ORDER BY idColumn DESC LIMIT 1
Variables:
Name: paramID
type: Integer
Default Value: -1
Runtime value: $_GET['itemid']