设置if else语句PDO

Question

如何设置PDO中的IF ELSE条件？

我希望能够回显结果，如果有的记录='N'。或者回显'空'。

$query = $db->prepare('SELECT student, subject FROM my_db WHERE faced = ? ORDER BY RAND() LIMIT 1'); 
$array = array('N'); 
$query->execute($array); 
if ($query>0){ 
$result = $query->fetchAll(PDO::FETCH_ASSOC); 
var_dump($result); 
} else { 
    echo 'Empty'; 
} 

Answer 1

你可以只执行检查之前的获取：

$query->execute($array); 
$result = $query->fetchAll(PDO::FETCH_ASSOC); 
if (count($result) > 0){ 
    var_dump($result); 
} else { 
    echo 'Empty'; 
} 

Answer 2

这里亚去！通过查询来完成：

SELECT 
Student, 
Subject, 
Max(CASE When faced ='N' then faced else 'Empty' End) as Faced 
FROM my_db 
group by student