PHP读取行数

Question

$count = mysql_query("SELECT COUNT(id) FROM users"); 

echo $count; 

这不起作用。错误消息资源标识未知＃21。
如何解决这个问题？

Answer 1

您应该使用fetchColumn()

$count = $db->query("SELECT COUNT(id) FROM users"); 

应该

$count = $db->query("SELECT COUNT(id) FROM users")->fetchColumn(); 

echo $count; //Returns number of rows 

Answer 2

使用本mysql_num_rows

$sql=mysql_query("SELECT COUNT(id) FROM users"); 
$count= mysql_num_rows($sql); 
echo $count ;