SELECT t1.id, t2.if FROM table1 AS t1, table2 AS t2 WHERE t1.rule=1 OR t2.rule=1

SELECT t1.id, t2.id FROM table1 AS t1
LEFT JOIN table2 AS t2 ON t1.related_column=t2.related_column
WHERE t1.rule=1 AND t2.rule=1

SELECT table1.ID, table2.ID FROM table1 as t1, table2 as t2 WHERE t1.anotherID=154 OR t2.anotherID=154

$query = 'SELECT table1.ID, table2.ID FROM table1 as t1, table2 as t2 WHERE this="1"';

$result = mysql_query($q);
while($row = mysql_fetch_array($result)) {

    // based on the string of ID's pulled from the joint query, retrieve additional data
    $dataquery = 'SELECT * FROM events WHERE ID="' . $row['ID'] . '" ';
    
    // echo out information

};

// results from first table

$query = 'SELECT ID FROM table1 WHERE this="1" GROUP BY ID';

$result = mysql_query($q);
while($row = mysql_fetch_array($result)) {

     // based on the string of ID's pulled from the joint query, retrieve additional data
     $dataquery = 'SELECT * FROM events WHERE ID="' . $row['ID'] . '" ';
    
     // echo out information based on the first tables results


   // store this ID in an array for cross checking to avoid duplication
   $array_id[] = $row['ID'];

};



// results for second table

  $query = 'SELECT ID FROM table2 WHERE this="1 GROUP BY ID"';
  
  $result = mysql_query($q);
  while($row = mysql_fetch_array($result)) {
  
    // if the ID was stored in an array previously, don't do the following...

   if(array_search($array_id, $row['ID']) == FALSE) {

          // based on the string of ID's pulled from the joint query, retrieve additional data
          $dataquery = 'SELECT * FROM events WHERE ID="' . $row['ID'] . '" ';
      
          // echo out information based on the first tables results
  
    }

  };

SELECT DISTINCT e. * FROM table1 AS t1
LEFT JOIN table2 AS t2 ON ( t1.ID != t2.ID )
LEFT JOIN events AS e ON ( e.ID = t1.ID OR e.ID = t2.ID )
WHERE t1.this='1' OR t2.this='1'

SELECT * FROM events AS t1
LEFT JOIN connectedEvents AS t2 ON ( t1.eventID != t2.eventID )
WHERE t1.typeID='1' OR t2.typeID='1'

SELECT * FROM events AS t1
LEFT JOIN connectedEvents AS t2 ON ( t1.eventID = t2.eventID )
WHERE t1.typeID='1' OR t2.typeID='1'

SELECT COUNT(events.eventID) FROM events, locations
                               WHERE events.locID = locations.locID AND locations.region_id='" . $row_region['region_id'] . "'
                               AND (DATE(CONCAT(events.year ,'-', events.month, '-', events.day, ' ', events.reghour, ':', events.regminute, ':00')) > DATE_ADD(NOW(), INTERVAL -1 day) )