How can SQL WHERE clauses be utilized to improve the filtering process in PHP?

When retrieving data from a database in PHP, SQL WHERE clauses can be utilized to filter the results based on specific criteria. This can help to narrow down the data being retrieved and make the process more efficient. By including WHERE clauses in SQL queries, you can specify conditions that must be met for a row to be included in the result set. 

// Connect to the database
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// SQL query with WHERE clause to filter results
$sql = "SELECT * FROM table_name WHERE column_name = 'criteria'";

$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // Output data of each row
    while($row = $result->fetch_assoc()) {
        echo "Column Name: " . $row["column_name"]. "<br>";
    }
} else {
    echo "0 results";
}

$conn->close();

Keywords

SQL WHERE clauses filtering process PHP functions libraries

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