If you are using Views 3 / Drupal 7 and looking for the answer to this question, it is baked right into Views. Where it says "add" next to filters, click the dropdown, then click "and/or; rearrange". It should be obvious from there.

Unfortunately this is still a missing feature in Views2. It has long been asked for and was promised a while ago, but seems to be a tricky piece of work and is now scheduled for Views3.

In the meantime you could try the Views Or module mentioned in that thread. As of today, it is still in dev status, but seems to be actively maintained and the issue queue does not look to bad, so you might want to give it a try.

I added it by concatenating the string.

It is relatively specific to the implementation - people would need to play with field to match for OR - node.title in the following code and the field to match it with - node_revisions.body in this case.

Extra piece of code to make sure that node_revisions.body is in the query.

/**
 * Implementation of hook_views_api().
 */
function eventsor_views_api() { // your module name into hook_views_api
  return array(
  'api' => 2,
  // might not need the line below, but in any case, the last arg is the name of your module
  'path' => drupal_get_path('module', 'eventsor'),
 );
}

/**
 *
 * @param string $form
 * @param type $form_state
 * @param type $form_id 
 */
function eventsor_views_query_alter(&$view, &$query) {

  switch ($view->name) {
    case 'Events':
      _eventsor_composite_filter($query);
      break;
  }
}

/**
 * Add to the where clause.
 * @param type $query 
 */
function _eventsor_composite_filter(&$query) {
  // If we see "UPPER(node.title) LIKE UPPER('%%%s%%')" - then add and to it.
  if (isset($query->where)) {

    $where_count = 0;
    foreach ($query->where as $where) {
      $clause_count = 0;
      if (isset($where['clauses'])) {
        foreach ($where['clauses'] as $clause) {
          $search_where_clause = "UPPER(node.title) LIKE UPPER('%%%s%%')";
          // node_data_field_long_description.field_long_description_value
          $desirable_where_clause = "UPPER(CONCAT_WS(' ', node.title, node_revisions.body)) LIKE UPPER('%%%s%%')";
          if ($clause == $search_where_clause) {
            //  $query->add_where('or', 'revisions.body = %s'); - outside of what we are looking for
            $query->where[$where_count]['clauses'][$clause_count] = $desirable_where_clause;

            // Add the field to the view, just in case.
            if (!isset($query->fields['node_revisions_body'])) {
              $query->fields['node_revisions_body'] = array(
                'field' => 'body',
                'table' => 'node_revisions',
                'alias' => 'node_revisions_body'
              );
            }
          }
          $clause_count++;
        }
      }
      $where_count++;
    }
  }
}