如何获取 sql 搜索查询的计数？

Question

如何获取 sql 搜索查询的计数

$u = new user();

$sql = "SELECT a.id FROM `accounts` AS a LEFT JOIN `users` AS u ON a.id = u.id WHERE a.id IS NOT NULL ";

$gender = $this->input->post('gender');

if($gender != NULL)
{
  $sql .= "AND u.gender = '".$gender."' ";
}

$u->query($sql);

如何计算 $u->query($sql); 中的查询结果数。我需要对其设置验证。如果查询结果计数为 0 ，我需要设置一条消息。我正在使用 PHP Codeigniter，datamapper 库。

谢谢！！！

Answer 1

像这样使用 count() 函数

...
$result = $u->query($sql);
$total_data = count($result);

Answer 2

$result = $this->db->get();

For Codeigniter use $count = $result->num_rows(); // HERE IS YOUR COUNT

For OOP PHP use $count = $result->num_rows; 

Answer 3

if($u->exists())
{
 echo "Found" // Do something
}
else
{
 echo "Nothing found" //Do something
}