PHP PDO::exec() Method: Usage and Examples

Executes SQL that does not return a result set and returns the number of affected rows.

The objective is to understand the behavior and operational limits, not only the method name.

What It Does

Executes SQL that does not return a result set and returns the number of affected rows.

Syntax and Return Value

PDO::exec(Parameter #0 [ <required> string $statement ]): mixed

The return value and exceptional cases depend on the call described here: Do not use exec to fetch SELECT rows; do not interpolate untrusted values into SQL.

Example 1: Basic Use

This self-contained SQLite example uses in-memory demo data; it requires the pdo_sqlite driver.

<?php
$pdo = new PDO('sqlite::memory:', null, null, [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]);
$pdo->exec('CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT NOT NULL, price INTEGER NOT NULL, active INTEGER)');
$pdo->exec("INSERT INTO products (id,name,price,active) VALUES (1,'Desk',120,1),(2,'Lamp',35,1),(3,'Chair',85,0)");
$affected = $pdo->exec("UPDATE products SET price = price + 48 WHERE id = 1");
echo "Updated rows: " . $affected;

Example 2: A Second Scenario

This self-contained SQLite example uses in-memory demo data; it requires the pdo_sqlite driver.

<?php
$pdo = new PDO('sqlite::memory:', null, null, [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]);
$pdo->exec('CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT NOT NULL, price INTEGER NOT NULL, active INTEGER)');
$pdo->exec("INSERT INTO products (id,name,price,active) VALUES (1,'Desk',120,1),(2,'Lamp',35,1),(3,'Chair',85,0)");
$affected = $pdo->exec("UPDATE products SET price = price + 62 WHERE id = 2");
echo "Updated rows: " . $affected;

Example 3: Practical Checks

This self-contained SQLite example uses in-memory demo data; it requires the pdo_sqlite driver.

<?php
$pdo = new PDO('sqlite::memory:', null, null, [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]);
$pdo->exec('CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT NOT NULL, price INTEGER NOT NULL, active INTEGER)');
$pdo->exec("INSERT INTO products (id,name,price,active) VALUES (1,'Desk',120,1),(2,'Lamp',35,1),(3,'Chair',85,0)");
$affected = $pdo->exec("UPDATE products SET price = price + 79 WHERE id = 3");
echo "Updated rows: " . $affected;

Important Behavior and Edge Cases

Do not use exec to fetch SELECT rows; do not interpolate untrusted values into SQL.

For production use, also account for error handling, data validation, resource limits and environment-specific driver behavior.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Executes SQL that does not return a result set and returns the number of affected rows.
• Do not use exec to fetch SELECT rows; do not interpolate untrusted values into SQL.
• prepare with bound parameters is appropriate for untrusted values.

Choose this API or pattern when its exact semantics match your task, and verify the result against the database driver and runtime used by your application.