How to query mysql in php and put it into an array

With the rapid development of Internet technology, PHP, as a scripting language, has been widely used. As an open source relational database management system, MySQL is widely used in the development of Web applications because of its advantages such as safety, reliability, and ease of use. In this article, we will introduce the method of using PHP to query MySQL and store data into an array for better data processing and analysis.

1. Preconditions

Before using PHP to query MySQL, you need to ensure that PHP and MySQL are installed and the connection between the two has been established. Connect to and gain access to the database using a connection string or information such as a username and password.

2. Connect to MySQL

Use PHP to connect to MySQL and select the database you want to access. You can use PHP extensions such as mysqli or PDO. This article takes the mysqli extension as an example.

First, you need to create a mysqli connection object. This object contains information about connecting to MySQL, as shown below:

$mysqli = new mysqli("localhost", "username", "password", "database");

Where localhost represents the address of the MySQL server; username represents the use when connecting to the database. The user name; password represents the password used when connecting to the database; database represents the name of the database to be accessed.

Then, you need to check whether the connection is successful:

if ($mysqli->connect_error) {
    die("连接失败: " . $mysqli->connect_error);
} else {
    echo "连接成功";
}

If the connection fails, "Connection failed" and an error message will be output; otherwise, "Connection successful" will be output.

3. Execute query statements

After connecting to MySQL and selecting the database to access, you can use SQL statements to query the data in the database. Using the mysqli extension, you can execute query statements through the following code:

$sql = "SELECT * FROM `table`";
$result = $mysqli->query($sql);

where $sql is the SQL statement to be executed, and $result is the query result set object.

4. Store query results in an array

To store query results in an array, you can use the fetch_array() method of the mysqli_result class. This method fetches a row of data from the result set and stores it in an array until all rows have been fetched. The following is a code example:

$data = array();
while ($row = $result->fetch_array()) {
    $data[] = $row;
}

Among them, $data is the array that stores the query results, and $row is each row of data obtained.

5. Full code example

To sum up, here is a complete PHP example code for querying MySQL and storing data into an array:

$mysqli = new mysqli("localhost", "username", "password", "database");
if ($mysqli->connect_error) {
    die("连接失败: " . $mysqli->connect_error);
} else {
    echo "连接成功";
}

$sql = "SELECT * FROM `table`";
$result = $mysqli->query($sql);

$data = array();
while ($row = $result->fetch_array()) {
    $data[] = $row;
}

print_r($data);

$mysqli->close();

The above code connects to MySQL, queries all the data in the data table, stores the query results in the array, and finally outputs the data in the array and closes the database connection.

Conclusion

This article introduces how to use PHP to query MySQL and store the query results in an array. By storing query results into arrays, data processing and analysis can be better performed, providing more possibilities for web application development.

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