php 从php中的mysql表中选择count(*)

select count(*) from table of mysql in php

提问by Gana

I am able to get both the value and row of the mysql query result.

我能够同时获得 mysql 查询结果的值和行。

But I am struggling to get the single output of a query. e.g.:

但我正在努力获得查询的单一输出。例如：

$result = mysql_query("SELECT COUNT(*) FROM Students;");

I need the result to display. But I am not getting the result.

我需要显示结果。但我没有得到结果。

I have tried with the following methods:

我尝试过以下方法：

1. mysql_fetch_assoc()
2. mysql_free_result()
3. mysql_fetch_row()

1. mysql_fetch_assoc()
2. mysql_free_result()
3. mysql_fetch_row()

But I didn't succeed to display (get) the actual value.

但是我没有成功显示（获取）实际值。

回答by Shakti Singh

You need to alias the aggregate using the askeyword in order to call it from mysql_fetch_assoc

您需要使用as关键字为聚合添加别名，以便从mysql_fetch_assoc

$result=mysql_query("SELECT count(*) as total from Students");
$data=mysql_fetch_assoc($result);
echo $data['total'];

回答by bmaupin

If you only need the value:

如果您只需要该值：

$result = mysql_query("SELECT count(*) from Students;");
echo mysql_result($result, 0);

回答by avetarman

$result = mysql_query("SELECT COUNT(*) AS `count` FROM `Students`");
$row = mysql_fetch_assoc($result);
$count = $row['count'];

Try this code.

试试这个代码。

回答by Lee Davis

Please start using PDO.

请开始使用 PDO。

mysql_* is deprecated as of PHP 5.5.0 and will be removed entirely in 7. Let's make it easier to upgrade and start using it now.

mysql_* 自 PHP 5.5.0 起已被弃用，并将在 7 中完全删除。让我们更轻松地升级并立即开始使用它。

$dbh = new \PDO($dsn, $user, $password);
$sth = $dbh->prepare('SELECT count(*) as total from Students');
$sth->execute();
print_r($sth->fetchAll());

回答by fatnjazzy

$num_result = mysql_query("SELECT count(*) as total_count from Students ") or exit(mysql_error());
$row = mysql_fetch_object($num_result);
echo $row->total_count;

回答by Raja Sekhar

here is the code for showing no of rows in the table with PHP

这是使用 PHP 显示表中没有行的代码

$sql="select count(*) as total from student_table";
$result=mysqli_query($con,$sql);
$data=mysqli_fetch_assoc($result);
echo $data['total'];

回答by Алексей Запруднов

For mysqli users, the code will look like this:

对于 mysqli 用户，代码如下所示：

$mysqli = new mysqli($db_host, $db_user, $db_pass, $db_name);

$result = $mysqli->query("SELECT COUNT(*) AS Students_count FROM Students")->fetch_array();
var_dump($result['Students_count']);

or:

或者：

$mysqli = new mysqli($db_host, $db_user, $db_pass, $db_name);

$result = $mysqli->query("SELECT COUNT(*) FROM Students")->fetch_array();
var_dump($result[0]);

回答by Sani Kamal

You need to alias the aggregate using the askeyword in order to call it from mysqli_fetch_assoc

您需要使用as关键字为聚合添加别名，以便从mysqli_fetch_assoc

$result=mysqli_query($conn,"SELECT count(*) as total from Students");
$data=mysqli_fetch_assoc($result);
echo $data['total'];

回答by Ram Pukar

$db  = new PDO('mysql:host=localhost;dbname=java_db', 'root', '') or die(mysql_errno());
$Sql = "SELECT count(*) as 'total' FROM users";
$stmt = $db->query($Sql);
$stmt->execute();
$data = array();
$total = $stmt->fetch(PDO::FETCH_ASSOC);
print '<pre>';
print_r($total);
print '</pre>';

Result:

结果：

回答by AndyLovesRuby

With mysql v5.7.20, here is how I was able to get the row count from a table using PHP v7.0.22:

使用 mysql v5.7.20，以下是我如何使用 PHP v7.0.22 从表中获取行数：

$query = "select count(*) from bigtable";
$qresult = mysqli_query($this->conn, $query);
$row = mysqli_fetch_assoc($qresult);
$count = $row["count(*)"];
echo $count;

The third line will return a structure that looks like this:

第三行将返回一个如下所示的结构：

array(1) {
   ["count(*)"]=>string(4) "1570"
}

In which case the ending echo statement will return:

在这种情况下，结束的 echo 语句将返回：

1570