Raw SQL when needed in Ruby on Rails - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to execute a raw SQL query using ActiveRecord.

Ruby on Rails

User.find_by_sql("SELECT * FROM users WHERE id = [1]")

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

A1

Bid

Cuser_id

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using a column name instead of a value.

Using a string without quotes in SQL.

The raw SQL query requires a specific value for the user ID, so '1' is the correct choice.

2fill in blank

medium

Complete the code to safely insert a variable into a raw SQL query using ActiveRecord.

Ruby on Rails

User.find_by_sql(["SELECT * FROM users WHERE email = ?", [1]])

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

Auser_email

Bemail

C:email

D"[e-mail]"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a symbol or variable name instead of a string.

Not quoting the email string.

When using parameterized queries, the value must be a string with quotes, so '"[e-mail]"' is correct.

3fill in blank

hard

Fix the error in the raw SQL query that fetches users with age greater than 30.

Ruby on Rails

User.find_by_sql("SELECT * FROM users WHERE age [1] 30")

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

A=

B>

C<

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' which selects only age 30.

Using '<' which selects younger users.

The query should select users older than 30, so the '>' operator is correct.

4fill in blank

hard

Fill both blanks to write a raw SQL query that selects users with name starting with 'A' and orders by created_at descending.

Ruby on Rails

User.find_by_sql("SELECT * FROM users WHERE name [1] 'A%' ORDER BY created_at [2]")

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

ALIKE

BASC

CDESC

D=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' instead of 'LIKE' for pattern matching.

Ordering ascending instead of descending.

Use 'LIKE' to match names starting with 'A' and 'DESC' to order newest first.

5fill in blank

hard

Fill all three blanks to write a raw SQL query that updates the user's email where id matches, using parameterized query.

Ruby on Rails

User.connection.execute(ActiveRecord::Base.send(:sanitize_sql_array, ["UPDATE users SET email = [1] WHERE id = [2]", [3]]))

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

A"[e-mail]"

Buser_id

D42

Attempts:

3 left

💡 Hint

Common Mistakes

Using unquoted strings for email.

Using variable names instead of actual values.

The email is a string, so use a quoted string for the first blank. The id is a number, so use 42 for the second and third blanks (the id value).