How to Check Row Existence in a Database with PDO?

Checking Row Existence in Database Using PDO

When dealing with databases, it's often necessary to verify the existence of a row based on specific criteria. PDO (PHP Data Objects) provides a handy way to execute SQL queries and retrieve the results.

Checking Row Existence:

To check if a row exists in a table using PDO, you can utilize the following code structure:

<code class="php">// Prepare the query
$stmt = $conn->prepare('SELECT * FROM table WHERE ID=?');

// Bind the parameter
$stmt->bindParam(1, $_GET['id'], PDO::PARAM_INT);

// Execute the query
$stmt->execute();

// Fetch the row
$row = $stmt->fetch(PDO::FETCH_ASSOC);

// Check if the row exists
if (!$row) {
    // Row does not exist
} else {
    // Row exists
}</code>

In this example, we are checking the existence of a row in a table based on the value of $_GET['id'].

Alternative Approaches:

Instead of fetching the row and checking its count, you can also directly access the return value of the PDOStatement object. If no rows are found, the return value will be false.

<code class="php">if (!$stmt->rowCount()) {
    // Row does not exist
}</code>

Furthermore, if you don't need to fetch the row data, you can have MySQL return a boolean value (1 or 0) by modifying the query:

<code class="php">$sql = 'SELECT 1 from table WHERE id = ? LIMIT 1';
$stmt = $conn->prepare($sql);
$stmt->execute([$_GET['id']]);

if ($stmt->fetchColumn()) {
    // Row exists
} else {
    // Row does not exist
}</code>

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