比较Drupal中的2个字段

Question

我想在Drupal中做一个简单的SQL查询，但我不知道如何。我想实现这一点：

SELECT COUNT(nid) AS i_count FROM node WHERE `created` != `changed`; 

我有下面的代码，它不工作：

$query = db_select('node', 'n'); 
$query->addExpression("COUNT(nid)","i_count"); 
$query->condition("created","changed","!="); 
$i_number_published = $query->execute()->fetchCol(); 

之所以它不工作是，它列created与比较字符串值"changed"。有什么办法可以告诉它比较列而不是列字符串？

Answer 1

使用where()成员函数基础上添加表中的其他领域条件：

$query = db_select('node', 'n'); 
$query->addExpression("COUNT(nid)","i_count"); 
$query->where("created != changed"); 
$i_number_published = $query->execute()->fetchCol(); 

Answer 2

$result_handler = db_query("select count(nid) from {node} where `created` != `changed`") ; 

$result_arr = db_fetch_array($result_handler) ; 

$number_of_nodes = $result_arr['count(nid)'] ;