Binds SELECT columns to PHP variables that are updated when each row is fetched.
The objective is to understand the behavior and operational limits, not only the method name.
What It Does
Binds SELECT columns to PHP variables that are updated when each row is fetched.
Syntax and Return Value
mysqli_stmt::bind_result(...)The return value and exceptional cases depend on the call described here: Provide one variable for every result column; the variables are passed by reference.
Requirements: install and enable the corresponding PHP driver or extension and configure the service before running the examples.
Example 1: Basic Use
The SELECT assumes users(id,email) in an actual MySQL database; output depends on its rows.
<?php
$host = getenv('DB_HOST'); $user = getenv('DB_USER'); $password = getenv('DB_PASSWORD'); $database = getenv('DB_NAME');
if (!$host || !$user || $password === false || !$database) throw new RuntimeException('Missing database configuration');
$mysqli = new mysqli($host, $user, $password, $database);
$mysqli->set_charset('utf8mb4');
$userId = 3;
$stmt = $mysqli->prepare("SELECT id, email FROM users WHERE id >= ? ORDER BY id");
$stmt->bind_param("i", $userId);
$stmt->execute();
$stmt->bind_result($id, $email);
while ($stmt->fetch()) echo $id . ":" . $email . PHP_EOL;Example 2: A Second Scenario
The SELECT assumes users(id,email) in an actual MySQL database; output depends on its rows.
<?php
$host = getenv('DB_HOST'); $user = getenv('DB_USER'); $password = getenv('DB_PASSWORD'); $database = getenv('DB_NAME');
if (!$host || !$user || $password === false || !$database) throw new RuntimeException('Missing database configuration');
$mysqli = new mysqli($host, $user, $password, $database);
$mysqli->set_charset('utf8mb4');
$userId = 5;
$stmt = $mysqli->prepare("SELECT id, email FROM users WHERE id >= ? ORDER BY id");
$stmt->bind_param("i", $userId);
$stmt->execute();
$stmt->bind_result($id, $email);
while ($stmt->fetch()) echo $id . ":" . $email . PHP_EOL;Example 3: Practical Checks
The SELECT assumes users(id,email) in an actual MySQL database; output depends on its rows.
<?php
$host = getenv('DB_HOST'); $user = getenv('DB_USER'); $password = getenv('DB_PASSWORD'); $database = getenv('DB_NAME');
if (!$host || !$user || $password === false || !$database) throw new RuntimeException('Missing database configuration');
$mysqli = new mysqli($host, $user, $password, $database);
$mysqli->set_charset('utf8mb4');
$userId = 8;
$stmt = $mysqli->prepare("SELECT id, email FROM users WHERE id >= ? ORDER BY id");
$stmt->bind_param("i", $userId);
$stmt->execute();
$stmt->bind_result($id, $email);
while ($stmt->fetch()) echo $id . ":" . $email . PHP_EOL;Important Behavior and Edge Cases
Provide one variable for every result column; the variables are passed by reference.
For production use, also account for error handling, data validation, resource limits and environment-specific driver behavior.
Comparison with Related Approaches
| Approach | Important distinction |
|---|---|
| mysqli_stmt::bind_result | Binds SELECT columns to PHP variables that are updated when each row is fetched. |
| Related API / pattern | get_result returns a mysqli_result object instead of bound output variables. |
Common Beginner Mistakes
| Mistake | Correct approach |
|---|---|
| Assuming the happy path covers edge cases | Provide one variable for every result column; the variables are passed by reference. |
| Using a related API interchangeably | get_result returns a mysqli_result object instead of bound output variables. |
Key Takeaways
- Binds SELECT columns to PHP variables that are updated when each row is fetched.
- Provide one variable for every result column; the variables are passed by reference.
- get_result returns a mysqli_result object instead of bound output variables.
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.