php - 如果查询结果为空，则回显错误消息

Question

如果查询为空，如何添加另一条错误消息？我试过mysqli_num_rows没有成功。：/

$que = new mysqli($host, $db_user, $db_password, $db_name);
$tbl = $que->query
("
 SELECT iditem, nazwa
 FROM  `idlist2` 
 WHERE nazwa LIKE  '%$name%'
");

while($value=$tbl->fetch_assoc())
{
    if(strlen($name) == 0 || strlen($name) == NULL)
    {
        echo '<font color="green">!</font>';
        break;
    }
    echo $value['iditem'] . $value['nazwa'] . "<br>";
}

标签： phpdatabasemysqli

Answer 1

这是一种方法：

while($value=$tbl->fetch_assoc())
{
    $notempty = true;                              // set a variable if you fetch anything
    if(strlen($name) == 0 || strlen($name) == NULL)
    {
        echo '<font color="green">!</font>';
         break;
    }
    echo $value['iditem'] . $value['nazwa'] . "<br>";
}
if (!isset($notempty)) {
    echo 'other error message';                   // show the other message if it isn't set
}