User feedback collection in No-Code - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ query_result

intermediate

Retrieve all feedback entries submitted in the last 7 days

Given a feedback database table with columns id, user_id, comment, and submitted_at, which query returns all feedback submitted in the last 7 days?

A SELECT * FROM feedback WHERE submitted_at < CURRENT_DATE + INTERVAL '7 days';

B SELECT * FROM feedback WHERE submitted_at >= CURRENT_DATE - INTERVAL '7 days';

C SELECT * FROM feedback WHERE submitted_at <= CURRENT_DATE - INTERVAL '7 days';

D SELECT * FROM feedback WHERE submitted_at > CURRENT_DATE + INTERVAL '7 days';

💡 Hint

Think about how to select dates from the recent past, not the future.

Option B correctly selects feedback where the submission date is within the last 7 days by subtracting 7 days from the current date. Other options either select future dates or dates older than 7 days.

🧠 Conceptual

intermediate

Understanding the purpose of a feedback table's user_id column

Why is the user_id column important in a user feedback collection database?

A It records the date and time when feedback was submitted.

B It stores the text of the feedback comment.

C It links feedback to the user who submitted it, enabling personalized follow-up.

D It counts the total number of feedback entries.

💡 Hint

Think about how to connect feedback to the person who gave it.

The user_id column connects each feedback entry to the specific user who submitted it, which helps in tracking and responding to feedback personally.

📋 Factual

advanced

Identify the syntax error in this feedback insertion query

Which option contains a syntax error when inserting a new feedback entry with user_id 5 and comment 'Great app!'?

A NSERT INTO feedback (user_id, comment) VALUES (5, 'Great app!');

B INSERT INTO feedback (user_id, comment) VALUES (5, 'Great app!');

C ;)'!ppa taerG' ,5( SEULAV )tnemmoc ,di_resu( kcabdeef OTNI TRESNI

D INSERT INTO feedback user_id, comment VALUES (5, 'Great app!');

💡 Hint

Check the syntax for specifying columns in an INSERT statement.

Option D is missing parentheses around the column names, which is required syntax in SQL INSERT statements.

❓ optimization

advanced

Optimize query to count feedback per user efficiently

Which query efficiently counts the number of feedback entries per user?

A SELECT user_id, COUNT(*) FROM feedback GROUP BY user_id;

B SELECT user_id, COUNT(*) FROM feedback;

C SELECT COUNT(user_id) FROM feedback GROUP BY user_id;

D SELECT user_id, COUNT(user_id) FROM feedback WHERE user_id IS NOT NULL;

💡 Hint

Think about grouping results by user to get counts per user.

Option A correctly groups feedback by user_id and counts entries per user. Option A lacks GROUP BY, C returns counts but no user_id, and D filters but misses grouping.

🔍 Analysis

expert

Find the cause of missing feedback entries in query result

A query to select feedback with comments containing 'bug' returns no rows, but there are entries with 'Bug' and 'BUG'. What is the cause?

No-Code

SELECT * FROM feedback WHERE comment LIKE '%bug%';

A The query is case-sensitive and misses 'Bug' and 'BUG' due to letter case differences.

B The query syntax is incorrect and causes no results.

C The feedback table is empty.

D The LIKE operator does not support wildcards.

💡 Hint

Consider how SQL handles text matching and case sensitivity.

The LIKE operator is case-sensitive in many databases, so it misses entries with different letter cases. Using case-insensitive search or functions can fix this.

Practice

1. What is the main purpose of collecting user feedback in a database?

easy

A. To delete old user data automatically

B. To store opinions that help improve products

C. To increase the size of the database

D. To prevent users from accessing the system

Solution

1. Step 1: Understand the role of user feedback

   User feedback is collected to learn what users think about a product or service.

2. Step 2: Connect feedback to product improvement

   Storing opinions helps teams improve features and fix problems.

3. Final Answer:

   To store opinions that help improve products -> Option B

4. Quick Check:

   User feedback = product improvement [OK]

Hint: Feedback stores opinions to improve products [OK]

Common Mistakes:

• Thinking feedback deletes data
• Confusing feedback with database size
• Assuming feedback blocks user access

2. Which of the following is the correct way to define a feedback table with fields for user name, rating, comment, and date?

easy

A. MAKE TABLE feedback (user_name CHAR, rate FLOAT, comment VARCHAR, date_time DATETIME);

B. CREATE feedback TABLE (user TEXT, stars TEXT, note TEXT, time TEXT);

C. TABLE feedback CREATE (name STRING, score NUMBER, feedback STRING, day DATE);

D. CREATE TABLE feedback (username TEXT, rating INTEGER, comment TEXT, date DATE);

Solution

1. Step 1: Identify correct SQL syntax for table creation

   The correct syntax starts with CREATE TABLE, followed by table name and fields with types.

2. Step 2: Match field names and types to feedback data

   username as TEXT, rating as INTEGER, comment as TEXT, and date as DATE are appropriate.

3. Final Answer:

   CREATE TABLE feedback (username TEXT, rating INTEGER, comment TEXT, date DATE); -> Option D

4. Quick Check:

   CREATE TABLE + fields = CREATE TABLE feedback (username TEXT, rating INTEGER, comment TEXT, date DATE); [OK]

Hint: CREATE TABLE with field names and types [OK]

Common Mistakes:

• Using wrong SQL keywords like MAKE or TABLE CREATE
• Incorrect data types for fields
• Wrong order of keywords

3. Given the feedback table below, what will this query return?

SELECT username, rating FROM feedback WHERE rating >= 4;

Table data:
username | rating | comment | date
alice | 5 | Great! | 2024-06-01
bob | 3 | Okay | 2024-06-02
carol | 4 | Good | 2024-06-03

medium

A. [{"username": "alice", "rating": 5}, {"username": "carol", "rating": 4}]

B. [{"username": "bob", "rating": 3}]

C. [{"username": "alice", "rating": 5}, {"username": "bob", "rating": 3}]

D. []

Solution

1. Step 1: Understand the query condition

   The query selects username and rating where rating is greater than or equal to 4.

2. Step 2: Check table rows against condition

   alice has rating 5 (>=4), carol has rating 4 (>=4), bob has rating 3 (<4).

3. Final Answer:

   [{"username": "alice", "rating": 5}, {"username": "carol", "rating": 4}] -> Option A

4. Quick Check:

   rating >= 4 returns alice and carol [OK]

Hint: Filter ratings >= 4 to get alice and carol [OK]

Common Mistakes:

• Including users with rating less than 4
• Selecting wrong columns
• Misreading >= as >

4. You wrote this query to add feedback but it gives an error:

INSERT INTO feedback (username, rating, comment, date) VALUES ('dave', 'five', 'Nice', '2024-06-04');

What is the likely cause of the error?

medium

A. The rating value 'five' is a string, but rating expects a number

B. The date format is incorrect

C. The comment field cannot contain text

D. The username field is missing

Solution

1. Step 1: Check data types in the INSERT statement

   Rating is expected as a number, but 'five' is a text string.

2. Step 2: Identify mismatch causing error

   Using a string where a number is expected causes a type error in the database.

3. Final Answer:

   The rating value 'five' is a string, but rating expects a number -> Option A

4. Quick Check:

   Rating type mismatch = The rating value 'five' is a string, but rating expects a number [OK]

Hint: Match data types exactly in INSERT statements [OK]

Common Mistakes:

• Using text instead of number for rating
• Assuming date format is wrong without checking
• Thinking comment cannot have text

5. You want to find all feedback comments from users who gave a rating less than 3 and sort them by date newest first. Which query achieves this?

hard

A. SELECT username, comment FROM feedback WHERE rating < 3 ORDER BY date ASC;

B. SELECT comment FROM feedback WHERE rating >= 3 ORDER BY date ASC;

C. SELECT username, comment FROM feedback WHERE rating < 3 ORDER BY date DESC;

D. SELECT username, comment FROM feedback ORDER BY rating DESC, date ASC;

Solution

1. Step 1: Filter feedback with rating less than 3

   The WHERE clause should use rating < 3 to get low ratings.

2. Step 2: Sort results by date descending

   ORDER BY date DESC sorts newest feedback first.

3. Final Answer:

   SELECT username, comment FROM feedback WHERE rating < 3 ORDER BY date DESC; -> Option C

4. Quick Check:

   Filter rating < 3 + ORDER BY date DESC = SELECT username, comment FROM feedback WHERE rating < 3 ORDER BY date DESC; [OK]

Hint: Use WHERE rating < 3 and ORDER BY date DESC [OK]

Common Mistakes:

• Using wrong comparison operator for rating
• Sorting dates ascending instead of descending
• Selecting wrong columns