How can PHP developers troubleshoot and debug SQL queries that are not returning the expected results?

To troubleshoot and debug SQL queries that are not returning the expected results, PHP developers can use tools like SQL debugging extensions, print out the generated SQL query for inspection, check for errors in the query syntax, and examine the data being returned by the query. 

// Example PHP code snippet to troubleshoot and debug SQL queries

// 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
$sql = "SELECT * FROM table WHERE column = 'value'";

// Print out the generated SQL query for inspection
echo "Generated SQL query: " . $sql . "<br>";

// Execute the query
$result = $conn->query($sql);

// Check for errors in the query execution
if (!$result) {
    echo "Error: " . $conn->error;
} else {
    // Fetch and display the data
    while ($row = $result->fetch_assoc()) {
        echo "Column: " . $row["column"] . "<br>";
    }
}

// Close the connection
$conn->close();

Keywords

SQL queries debugging PHP developers troubleshooting unexpected results

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