CHECK constraint in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a CHECK constraint that ensures age is at least 18.

SQL

CREATE TABLE users (id INT, age INT [1] chk_age CHECK (age >= 18));

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ADEFAULT

BPRIMARY KEY

CCHECK

DCONSTRAINT

Attempts:

3 left

💡 Hint

Common Mistakes

Using DEFAULT instead of CONSTRAINT

Using PRIMARY KEY where CHECK is needed

Omitting CONSTRAINT keyword

The CONSTRAINT keyword is used to name or define a constraint such as CHECK in a table definition.

2fill in blank

medium

Complete the code to add a CHECK constraint that ensures salary is positive.

SQL

ALTER TABLE employees ADD [1] chk_salary CHECK (salary > 0);

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ACONSTRAINT

BINDEX

CDEFAULT

DPRIMARY KEY

Attempts:

3 left

💡 Hint

Common Mistakes

Using INDEX instead of CONSTRAINT

Using DEFAULT keyword incorrectly

Omitting CONSTRAINT keyword

The CONSTRAINT keyword is used to add a CHECK constraint to an existing table.

3fill in blank

hard

Fix the error in the CHECK constraint that should ensure quantity is non-negative.

SQL

CREATE TABLE orders (id INT, quantity INT [1] CHECK (quantity >= 0));

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ACHECK

BCONSTRAINT

CDEFAULT

DPRIMARY KEY

Attempts:

3 left

💡 Hint

Common Mistakes

Missing parentheses around the condition

Using CONSTRAINT without CHECK keyword

Using DEFAULT instead of CHECK

The CHECK keyword must be followed by parentheses enclosing the condition. The code is missing parentheses around quantity >= 0.

4fill in blank

hard

Fill both blanks to create a CHECK constraint that ensures rating is between 1 and 5 inclusive.

SQL

CREATE TABLE reviews (id INT, rating INT [1] chk_rating CHECK (rating [2] 1 AND rating <= 5));

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ACONSTRAINT

B>=

C<=

DDEFAULT

Attempts:

3 left

💡 Hint

Common Mistakes

Using DEFAULT instead of CONSTRAINT

Using < instead of >= for the lower bound

Omitting CONSTRAINT keyword

Use CONSTRAINT to define the constraint and >= to check rating is at least 1.

5fill in blank

hard

Fill all three blanks to add a named CHECK constraint that ensures price is positive and less than 1000.

SQL

ALTER TABLE products ADD [1] price_check [2] CHECK (price [3] 0 AND price < 1000);

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ACONSTRAINT

B>

CCHECK

DDEFAULT

Attempts:

3 left

💡 Hint

Common Mistakes

Using DEFAULT instead of CONSTRAINT

Using >= instead of > for price positivity

Omitting CHECK keyword

Use CONSTRAINT to name the constraint, CHECK to define it, and > to ensure price is positive.