PHP MySQL Get Last Inserted ID – Complete Beginner Tutorial

When working with MySQL databases, many tables use an AUTO_INCREMENT primary key. After inserting a new record, you often need to know which ID was generated. This is useful for:

• Creating user profiles
• Linking related tables
• Redirecting users
• Logging activities

This tutorial explains how to get the last inserted ID in PHP MySQL using different methods, with examples and output.

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What Is Last Inserted ID in PHP MySQL?

The last inserted ID is the AUTO_INCREMENT value generated by MySQL when a new row is inserted into a table.

Example:

INSERT INTO users (name, email) VALUES ('Rahul', 'rahul@example.com');

If the ID column is auto-incremented, MySQL automatically assigns a new ID. PHP can retrieve this value.

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When Do You Need the Last Inserted ID?

You need the last inserted ID when:

• Inserting user data and creating a profile page
• Saving order details and order items
• Inserting parent-child table records
• Tracking newly created database entries

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Prerequisites for Getting Last Inserted ID

Before proceeding, ensure you have:

• PHP installed
• MySQL database with AUTO_INCREMENT column
• A working MySQLi database connection
• Basic understanding of INSERT queries

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Sample MySQL Table Used in Examples

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(100),
    email VARCHAR(100)
);

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PHP MySQL Database Connection Code

<?php
$conn = mysqli_connect("localhost", "root", "", "testdb");

if (!$conn) {
    die("Database connection failed");
}
?>

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Get Last Inserted ID Using mysqli_insert_id()

The mysqli_insert_id() function is the most common way to retrieve the last inserted ID.

<?php
$query = "INSERT INTO users (name, email)
          VALUES ('Amit', 'amit@gmail.com')";

if (mysqli_query($conn, $query)) {
    $last_id = mysqli_insert_id($conn);
    echo "Last Inserted ID: " . $last_id;
}
?>

Output:

Last Inserted ID: 5

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Get Last Inserted ID After Insert with Variables

<?php
$name = "Neha";
$email = "neha@gmail.com";

$query = "INSERT INTO users (name, email)
          VALUES ('$name', '$email')";

mysqli_query($conn, $query);
echo "Inserted ID: " . mysqli_insert_id($conn);
?>

Output:

Inserted ID: 6

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Get Last Inserted ID Using Prepared Statements

When using prepared statements, the method remains the same.

<?php
$stmt = mysqli_prepare($conn,
        "INSERT INTO users (name, email) VALUES (?, ?)");

mysqli_stmt_bind_param($stmt, "ss", $name, $email);

$name = "Ravi";
$email = "ravi@gmail.com";

mysqli_stmt_execute($stmt);

echo "Last Inserted ID: " . mysqli_insert_id($conn);
?>

Output:

Last Inserted ID: 7

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Get Last Inserted ID and Use It in Another Query

This is common when inserting related data.

<?php
mysqli_query($conn,
    "INSERT INTO users (name, email)
     VALUES ('Pooja', 'pooja@gmail.com')");

$user_id = mysqli_insert_id($conn);

mysqli_query($conn,
    "INSERT INTO profiles (user_id, bio)
     VALUES ($user_id, 'Web Developer')");

echo "User and profile created successfully";
?>

Output:

User and profile created successfully

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Important Rules for Getting Last Inserted ID

• Works only for AUTO_INCREMENT columns
• Returns ID generated by the last INSERT query
• Must be called on the same database connection
• Not affected by SELECT queries

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Common Mistakes When Getting Last Inserted ID

• Calling mysqli_insert_id() before INSERT
• Using a different database connection
• Forgetting AUTO_INCREMENT column
• Expecting ID after UPDATE query

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Best Practices for Using Last Inserted ID in PHP

• Always check INSERT success before fetching ID
• Use transactions when inserting multiple related records
• Keep the same database connection
• Use prepared statements for security

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Related tutorial:

• PHP MySQL Insert Data
• PHP MySQL Select Data
• PHP MySQL Update Data
• PHP MySQL Use WHERE

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Frequently Asked Questions (FAQ)

1. What function gets the last inserted ID in PHP MySQL?

mysqli_insert_id().

2. Does it work with prepared statements?

Yes, it works the same way.

3. Can I get last ID after UPDATE?

No, only after INSERT.

4. Does SELECT affect last inserted ID?

No, SELECT queries do not affect it.

5. Is last inserted ID session-specific?

Yes, it is connection-specific.