title: MySQL count, left join, group by to return zero rows
body: <p>In the below sql statement:</p>
  
  <pre><code> SELECT `keywords`.keyID, count(`keywords-occurencies`.keyID) as countOccurencies 
                      FROM `keywords-occurencies`  
                      LEFT JOIN `keywords` 
                      ON `keywords-occurencies`.keyID = `keywords`.keyID 
                      WHERE `keywords-occurencies`.`keyID` IN (1,2,3) AND date BETWEEN '2013/01/25' AND '2013/01/27'
                      GROUP BY `keywords`.`keyID`
  </code></pre>
  
  <p>If keyID 3 has no return values it is not counted as 0 and it is not included in the result set and a result like this is displayed</p>
  
  <pre><code>keyID countOccurencies
  1       3
  3       5
  </code></pre>
  
  <p>I would like to display the zero results like</p>
  
  <pre><code>keyID countOccurencies
  1       3
  2       0
  3       5
  </code></pre>
  
  <p>Sample data to test with:</p>
  
  <pre><code>--
  -- Table structure for table `keywords`
  --
  
  CREATE TABLE IF NOT EXISTS `keywords` (
    `keyID` int(10) unsigned NOT NULL AUTO_INCREMENT,
    `keyName` varchar(40) NOT NULL,
    PRIMARY KEY (`keyID`)
  ) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ;
  
  --
  -- Dumping data for table `keywords`
  --
  
  INSERT INTO `keywords` (`keyID`, `keyName`) VALUES
  (1, 'testKey1'),
  (2, 'testKey2');
  
  -- --------------------------------------------------------
  
  --
  -- Table structure for table `keywords-occurencies`
  --
  
  CREATE TABLE IF NOT EXISTS `keywords-occurencies` (
    `occurencyID` int(10) unsigned NOT NULL AUTO_INCREMENT,
    `keyID` int(10) unsigned NOT NULL,
    `date` date NOT NULL,
    PRIMARY KEY (`occurencyID`),
    KEY `keyID` (`keyID`)
  ) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ;
  
  --
  -- Dumping data for table `keywords-occurencies`
  --
  
  INSERT INTO `keywords-occurencies` (`occurencyID`, `keyID`, `date`) VALUES
  (1, 1, '2013-01-27'),
  (2, 1, '2013-01-26');
  
  --
  -- Constraints for table `keywords-occurencies`
  --
  ALTER TABLE `keywords-occurencies`
    ADD CONSTRAINT `keywords@002doccurencies_ibfk_1` FOREIGN KEY (`keyID`) REFERENCES `keywords` (`keyID`) ON DELETE CASCADE ON UPDATE CASCADE;
  </code></pre>