How to output query data to the page in php

In web development, PHP is a widely used dynamic web page programming language. PHP query is an essential step when we need to retrieve data from the database and display it on a Web page. This article will introduce how to use PHP to query data from the database and output it to a Web page.

1. Connect to the database

First, we need to connect to the database. In PHP, we use the mysqli_connect() function to connect to the MySQL database. This function requires four parameters: server name, username, password, and database name.

For example:

$con = mysqli_connect("localhost", "my_user", "my_password", "my_db");

The above code will connect to a MySQL database named "my_db" and use "my_user" as the username and "my_password" as the password, and the database is located on localhost .

2. Query data

Next, we need to get data from the database. In PHP, we use the mysqli_query() function to execute SQL query statements. This function requires two parameters: the variable connected to the MySQL server and the SQL query statement.

For example:

$result = mysqli_query($con, "SELECT * FROM my_table");

The above code will select all data from the database table named "my_table". The results of the query will be stored in the variable $result.

3. Output to page

Now, we have obtained the required data from the database. Next, we output this data to a web page. In PHP, we use the mysqli_fetch_array() function to fetch data from the query results row by row and output it to the Web page.

For example:

while($row = mysqli_fetch_array($result)) {
    echo $row['id'] . " " . $row['name'];
    echo "<br>";
}

The above code will output the "id" and "name" columns in the query result set row by row. Each line of output will be delimited using HTML's "br" tag.

The complete code is as follows:

$con = mysqli_connect("localhost","my_user","my_password","my_db");
$result = mysqli_query($con, "SELECT * FROM my_table");

while($row = mysqli_fetch_array($result)) {
    echo $row['id'] . " " . $row['name'];
    echo "<br>";
}

The above code will connect to the MySQL database, select all data from the table named "my_table", and output each row of data to the Web page.

This article describes how to use PHP to query data from the database and output it to a Web page. By mastering these basic query and output techniques, you can easily build powerful web applications.

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