在fetch_array之后获取num_rows的正确命令顺序(mysqli OOP) [英] Proper command order to get num_rows after fetch_array (mysqli OOP)

问题描述

以数组形式获取结果时遇到num_row的问题:

I'm having a problem getting a num_row when I fetch the results as an array:

$sql = "SELECT * FROM people WHERE peopleid=?";
if (!($stmt = $mysqli->prepare($sql))) {
echo "stmt Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}

if (!$stmt->bind_param("i", $_GET['peopleid'])) {
echo "Binding parameters failed: (" . $stmt->errno . ") " . $stmt->error;
}

if (!$stmt->execute()) {
   echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
}

$stmt->store_result();
$exist=$stmt->num_rows;
$result = $stmt->get_result();
$peopleres  = $result->fetch_array(MYSQLI_ASSOC); // this does work :)
if ($exist == 0) {
//do something it it's zero
}

如果在示例中将store_results和num_rows放在其中，则会得到

If I place the store_results and num_rows where it is in the example I get an

在发生非对象错误时调用成员函数fetch_array().

Call to a member function fetch_array() on a non-object error.

如果我将其放置在fetch_array之后，它将始终等于零.我以前曾经成功使用过num_rows，但这是我第一次尝试与fetch_array一起使用.

If I place it after the fetch_array it's always equal to zero. I've used num_rows successfully before, but this is the first time I'm trying to use it alongside a fetch_array.

推荐答案

看一下文档

mysqli_result :: $ num_rows
int $mysqli_result->num_rows;

mysqli_result::$num_rows
int $mysqli_result->num_rows;

如果出于某些原因，请使用num_rows代替

If you want for some reason use num_rows instead of

$stmt->store_result();
$exist=$stmt->num_rows;
$result = $stmt->get_result();
$peopleres  = $result->fetch_array(MYSQLI_ASSOC); // this does work :)
if ($exist == 0) {
//do something it it's zero
}

您可以尝试

$result = $stmt->get_result();
$exist = $result->num_rows;
if ($exist == 0) {
    //do something it it's zero
}
$row = $result->fetch_array(MYSQLI_ASSOC);

---

现在，如果您只是检查结果集中是否有任何行，那么使用num_rows并不是绝对必要的，因为您已经在客户端上获得了结果集.您可以尝试获取一行

---

Now if you're just checking whether you have any rows in the resultset or not the usage of num_rows is not absolutely necessary since you already get your resultset on the client. You can just try to fetch a row

$result = $stmt->get_result();
if (!$row = $result->fetch_array(MYSQLI_ASSOC)) {
    //do something if there's no row
} else {
    //do what you have to do with you data in the row
    echo 'peopleid: ' . $row['peopleid'];
}

这篇关于在fetch_array之后获取num_rows的正确命令顺序(mysqli OOP)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！