PHP PDOStatement::fetchColumn() Method: Usage and Examples

Returns a value from a specified column in the next result row.

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

What It Does

Returns a value from a specified column in the next result row.

Syntax and Return Value

PDOStatement::fetchColumn(Parameter #0 [ <optional> int $column = 0 ]): mixed

The return value and exceptional cases depend on the call described here: False can mean end-of-data, so selecting a boolean false requires careful handling.

Example 1: Basic Use

The statement has a real query and result set; database-specific metadata and statement options may be unsupported.

<?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)");
$stmt = $pdo->prepare("SELECT COUNT(*) FROM products WHERE price >= ?");
$stmt->execute([48]);
echo $stmt->fetchColumn();

Example 2: A Second Scenario

The statement has a real query and result set; database-specific metadata and statement options may be unsupported.

<?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)");
$stmt = $pdo->prepare("SELECT COUNT(*) FROM products WHERE price >= ?");
$stmt->execute([62]);
echo $stmt->fetchColumn();

Example 3: Practical Checks

The statement has a real query and result set; database-specific metadata and statement options may be unsupported.

<?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)");
$stmt = $pdo->prepare("SELECT COUNT(*) FROM products WHERE price >= ?");
$stmt->execute([79]);
echo $stmt->fetchColumn();

Important Behavior and Edge Cases

False can mean end-of-data, so selecting a boolean false requires careful handling.

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

• Returns a value from a specified column in the next result row.
• False can mean end-of-data, so selecting a boolean false requires careful handling.
• fetch returns the whole next row.

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.