How to query the number of mysql data in php

The method for php to query the number of mysql data is: 1. Create a PHP sample file and establish a connection to the MySQL database through the "mysqli_connect()" function; 2. After the connection is established, execute the SQL query statement to obtain Results and put the query into PHP code and send it to MySQL using the "mysqli_query()" function; 3. Use the `mysqli_fetch_array()` function to retrieve the actual results, and then close the MySQL connection.

Operating system for this tutorial: Windows 10 system, php8.1.3 version, Dell G3 computer.

To query the number of data (i.e. the number of rows) in mysql, you can use the functions provided by PHP and MySQL.

The following are detailed examples of methods and code.

1. In PHP, you first need to establish a connection to the MySQL database. This can be done through the `mysqli_connect()` function. Connection variables are stored in variables for later use.

```php
$conn = mysqli_connect($servername, $username, $password, $dbname);
```

Where `$servername` is the name of the MySQL server, `$username` is the username used to access the database, `$password` is the corresponding password, `$dbname` is the database to be accessed The name.

2. Once the connection has been established, we can execute the SQL query statement and obtain the results. To query the number of rows in a table, you can use the following SQL query:

```sql
SELECT COUNT(*) FROM table_name;
```

`table_name` is the target table to be queried.

Put this query into PHP code and send it to MySQL using the `mysqli_query()` function.

```php
$sql = "SELECT COUNT(*) FROM table_name";
$result = mysqli_query($conn, $sql);
```

Now `$result` contains a pointer to the query result. In order to retrieve the actual results, we can use the `mysqli_fetch_array()` function.

```php
$row = mysqli_fetch_array($result, MYSQLI_NUM);
$count = $row[0];
```

Now, the variable `$count` contains the number of rows in the table. Finally, we should close the MySQL connection.

```php
mysqli_close($conn);
```

To sum up, here is the complete PHP code on how to query the number of rows in a MySQL table:

```php
<?php
$servername = "localhost";
$username = "yourusername";
$password = "yourpassword";
$dbname = "yourdbname";
$conn = mysqli_connect($servername, $username, $password, $dbname);
$sql = "SELECT COUNT(*) FROM table_name";
$result = mysqli_query($conn, $sql);
$row = mysqli_fetch_array($result, MYSQLI_NUM);
$count = $row[0];
mysqli_close($conn);
echo "Number of rows: " . $count;
?>
```

The above is the detailed content of How to query the number of mysql data in php. For more information, please follow other related articles on the PHP Chinese website!