How to write database reports in PHP

How to write database reports in PHP

Database reports are a common data analysis tool. By displaying the data in the database in a specific format, users can more intuitively understand the relationships and trends between the data. PHP, as a common Web programming language, can also be used to write database reports. In this article, we will introduce some methods of writing database reports in PHP.

1. Use PHP to connect to the database

First, we need to use PHP to connect to the database. In PHP, this can be achieved using extension libraries such as mysqli or PDO. Specifically, you can connect to the MySQL database through the following code:

$conn = mysqli_connect($host, $username, $password, $database);

Among them, $host represents the database server address, $username represents the database user name, $password represents the database password, and $database represents the name of the database to be connected.

2. Read data from the database

After connecting to the database, we need to read data from the database. Generally speaking, this can be achieved through SQL statements. For example, the following code can read the names and grades of all students from a table named students:

$sql = "SELECT name, score FROM students";
$result = mysqli_query($conn, $sql);

In this code, $sql represents the executed SQL statement, and the mysqli_query() function is used to execute Query and store the results in the $result variable.

3. Formatting data

After reading the data from the database, we need to format the data for better display. For example, the data can be presented in the form of tables or charts. The following is a simple example for displaying data as an HTML table:

echo "<table>";
echo "<tr><th>Name</th><th>Score</th></tr>";
while ($row = mysqli_fetch_assoc($result)) {
    echo "<tr><td>" . $row["name"] . "</td><td>" . $row["score"] . "</td></tr>";
}
echo "</table>";

In this code, use the mysqli_fetch_assoc() function to obtain each row of data and output it to the HTML table in turn.

4. Add query conditions

Sometimes, we need to filter the data in the database, for example, only query data that meets certain specific conditions. In PHP, you can use the WHERE statement to specify query conditions. For example, the following code can query all students with scores greater than 80 points:

$sql = "SELECT name, score FROM students WHERE score > 80";
$result = mysqli_query($conn, $sql);

Similarly, you can also use the ORDER BY statement to sort the query results, use the LIMIT statement to limit the number of query results, etc.

5. Output charts

In addition to displaying data as tables, we can also display data as various charts, such as bar charts, line charts, etc. In PHP, this can be achieved using various charting libraries. For example, you can use the Google Charts library to draw charts. The following code can display the data as a simple histogram:

echo "<script type='text/javascript' src='https://www.gstatic.com/charts/loader.js'></script>";
echo "<script type='text/javascript'>";
echo "google.charts.load('current', {packages: ['corechart', 'bar']});";
echo "google.charts.setOnLoadCallback(drawChart);";
echo "function drawChart() {";
echo "    var data = google.visualization.arrayToDataTable([";
echo "        ['Name', 'Score'],";
while ($row = mysqli_fetch_assoc($result)) {
    echo "        ['" . $row["name"] . "', " . $row["score"] . "],";
}
echo "    ]);";
echo "    var options = {";
echo "        chartArea: {width: '50%'},";
echo "        hAxis: {title: 'Score', minValue: 0},";
echo "        vAxis: {title: 'Name'},";
echo "    };";
echo "    var chart = new google.visualization.BarChart(document.getElementById('chart_div'));";
echo "    chart.draw(data, options);";
echo "}";
echo "</script>";
echo "<div id='chart_div'></div>";

In this code, the Google Charts library is used to draw the histogram, and the data is read from the database and formatted to be suitable for drawing the histogram. format.

Summary

PHP is a widely used web programming language that can also be used to write database reports. In this article, we introduce some methods of writing database reports in PHP, including connecting to the database, reading data from the database, formatting data, adding query conditions and output charts, etc. These methods can help us realize various complex data analysis needs more conveniently and improve work efficiency.

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