How do I update a column value in my custom plugin with a simple controller?
You are currently performing a SELECTinstead of an UPDATE so no data will be updated.

I'm guessing that entryId is the primary key of the record you are trying to update? If so, I would suggest you find the record to make sure it exists, update its attributes (status) and then save it.

// PluginController
public function actionDeny()
{
    $this-&gt;requirePostRequest();

    $status  = PluginStatus::Denied;
    $entryId = craft()-&gt;request-&gt;getRequiredPost('entryId');

    if (craft()-&gt;pluginName-&gt;updateStatus($entryId, $status)
    {
        craft()-&gt;userSession-&gt;setError(Craft::t('Unable to deny the entry.'));
    }
    else
    {
        craft()-&gt;userSession-&gt;setNotice(Craft::t('The entry was denied.'));
    }
}

// PluginService
public function updateStatus($id, $status)
{
    $record = PluginRecord::model()-&gt;findById($id);

    if ($record)
    {
        $record-&gt;setAttribute('status', $status);

        return $record-&gt;save();
    }
    else
    {
        throw new Exception(Craft:t('No record was found with id {id}', array('id' =&gt; $id));
    }
}


Unless I'm missing something, that should be about all you need.

@selvinortiz