AUTO_INCREMENT behavior in MySQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a table with an auto-incrementing primary key.

MySQL

CREATE TABLE users (id INT [1] PRIMARY KEY, name VARCHAR(100));

Drag options to blanks, or click blank then click option'

AAUTO_INCREMENT

BNOT NULL

CUNIQUE

DDEFAULT 0

Attempts:

3 left

💡 Hint

Common Mistakes

Using NOT NULL instead of AUTO_INCREMENT will not auto-generate values.

Forgetting to set the column as PRIMARY KEY with AUTO_INCREMENT.

The AUTO_INCREMENT keyword makes the id column automatically increase by 1 for each new row.

2fill in blank

medium

Complete the code to insert a new user without specifying the auto-increment column.

MySQL

INSERT INTO users (name) VALUES ([1]);

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ANULL

B1

C'id'

D'Alice'

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to insert a value into the auto-increment column manually.

Using NULL as a value for the name column.

When inserting, you do not specify the id column; the database assigns it automatically. Here, we insert the name 'Alice'.

3fill in blank

hard

Fix the error in the insert statement to let auto-increment work correctly.

MySQL

INSERT INTO users (id, name) VALUES ([1], 'Bob');

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A0

BNULL

CDEFAULT

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Inserting a fixed number instead of NULL for the auto-increment column.

Using DEFAULT keyword which is not valid in VALUES clause.

To let MySQL auto-generate the id, insert NULL or omit the column. Using NULL tells MySQL to assign the next auto-increment value.

4fill in blank

hard

Fill both blanks to reset the auto-increment counter to 1 for the table.

MySQL

ALTER TABLE users [1] = [2];

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AAUTO_INCREMENT

B1

CRESET

DSTART

Attempts:

3 left

💡 Hint

Common Mistakes

Using RESET or START keywords which are not valid in this context.

Trying to set AUTO_INCREMENT without a value.

To reset the auto-increment counter, use ALTER TABLE users AUTO_INCREMENT = 1;. This sets the next auto-increment value to 1.

5fill in blank

hard

Fill all three blanks to create a table with an auto-increment column, insert a row, and select the auto-generated id.

MySQL

CREATE TABLE products (product_id INT [1] PRIMARY KEY, name VARCHAR(50));
INSERT INTO products (name) VALUES ([2]);
SELECT [3] FROM products WHERE name = 'Table';

Drag options to blanks, or click blank then click option'

AAUTO_INCREMENT

B'Table'

Cproduct_id

DNOT NULL

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting AUTO_INCREMENT in the table definition.

Inserting the id manually instead of letting it auto-increment.

Selecting the wrong column in the SELECT statement.

First, create the table with AUTO_INCREMENT on product_id. Then insert a product named 'Table'. Finally, select the product_id for that product.