AUTO_INCREMENT behavior in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

SQL

CREATE TABLE users (id INT [1] PRIMARY KEY, name VARCHAR(50));

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AVARCHAR(10)

BAUTO_INCREMENT

CINTEGER

DPRIMARY KEY

Attempts:

3 left

💡 Hint

Common Mistakes

Using just INTEGER without AUTO_INCREMENT.

Putting PRIMARY KEY twice.

Using VARCHAR for an auto-incrementing number.

The AUTO_INCREMENT keyword makes the id column automatically increase with each new row.

2fill in blank

medium

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

SQL

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

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ANULL

B1

C'Alice'

D'id'

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to insert a value for the auto-increment column.

Using NULL instead of a name string.

Inserting the column name instead of a value.

When inserting, you only provide the name. The id is generated automatically.

3fill in blank

hard

Fix the error in the code to reset the auto-increment counter to 1.

SQL

ALTER TABLE users [1] = 1;

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AAUTO_INCREMENT

BRESTART

CINCREMENT

DRESET

Attempts:

3 left

💡 Hint

Common Mistakes

Using RESET or RESTART which are not valid keywords here.

Trying to use INCREMENT instead of AUTO_INCREMENT.

The correct syntax to reset the auto-increment value is to set AUTO_INCREMENT to 1.

4fill in blank

hard

Fill both blanks to create a table where the auto-increment starts at 1000.

SQL

CREATE TABLE orders (order_id INT [1] PRIMARY KEY) [2];

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AAUTO_INCREMENT

BSTART WITH 1000

CAUTO_INCREMENT=1000

DINCREMENT BY 10

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'START WITH' or 'INCREMENT BY 10' which are not valid in this SQL dialect.

Putting the starting value inside the column definition.

The AUTO_INCREMENT keyword defines the column, and AUTO_INCREMENT=1000 sets the starting value for the table.

5fill in blank

hard

Fill in the blanks to select the next auto-increment value, insert a new row, and then get the last inserted id.

SQL

SELECT [1] FROM information_schema.tables WHERE table_name = 'users';
INSERT INTO users (name) VALUES ('Bob');
SELECT [2]();

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AAUTO_INCREMENT

BLAST_INSERT_ID

DMAX(id)

Attempts:

3 left

💡 Hint

Common Mistakes

Using MAX(id) instead of LAST_INSERT_ID() to get the last inserted id.

Confusing AUTO_INCREMENT keyword with function names.

The first query gets the next auto-increment value. The last query gets the id of the last inserted row using LAST_INSERT_ID().