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

Runs a SQL statement immediately and returns a PDOStatement for result-producing statements.

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

What It Does

Runs a SQL statement immediately and returns a PDOStatement for result-producing statements.

Syntax and Return Value

PDO::query(Parameter #0 [ <required> string $query ], Parameter #1 [ <optional> ?int $fetchMode = null ], Parameter #2 [ <optional> mixed ...$fetchModeArgs ]): mixed

The return value and exceptional cases depend on the call described here: Never concatenate user input into a query string; use prepare for dynamic values.

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)");
$result = $pdo->query("SELECT name FROM products WHERE price >= 48 ORDER BY id");
foreach ($result as $row) { echo $row["name"] . PHP_EOL; }

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)");
$result = $pdo->query("SELECT name FROM products WHERE price >= 62 ORDER BY id");
foreach ($result as $row) { echo $row["name"] . PHP_EOL; }

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)");
$result = $pdo->query("SELECT name FROM products WHERE price >= 79 ORDER BY id");
foreach ($result as $row) { echo $row["name"] . PHP_EOL; }

Important Behavior and Edge Cases

Never concatenate user input into a query string; use prepare for dynamic values.

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

• Runs a SQL statement immediately and returns a PDOStatement for result-producing statements.
• Never concatenate user input into a query string; use prepare for dynamic values.
• exec is intended for statements without result rows.

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.