NOW, CURDATE, CURTIME in MySQL - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ query_result

intermediate

What does the query return?

Consider the query:

SELECT CURDATE();

What is the output format of this query?

MySQL

SELECT CURDATE();

A A string in 'HH:MM:SS' format representing current time

B A string in 'YYYY-MM-DD' format representing today's date

C A datetime value including date and time

D An integer representing the current timestamp

💡 Hint

CURDATE() returns only the date part, not time.

CURDATE() returns the current date as a string in 'YYYY-MM-DD' format without time.

❓ query_result

intermediate

What is the output of NOW()?

Given the query:

SELECT NOW();

What does this function return?

MySQL

SELECT NOW();

A Only the current time in 'HH:MM:SS' format

B Only the current date in 'YYYY-MM-DD' format

C The current date and time as a datetime value in 'YYYY-MM-DD HH:MM:SS' format

D The Unix timestamp as an integer

💡 Hint

NOW() returns both date and time.

NOW() returns the current date and time as a datetime string like '2024-06-15 14:30:00'.

❓ query_result

advanced

What is the output of CURTIME()?

What does the query below return?

SELECT CURTIME();

MySQL

SELECT CURTIME();

A The current time as a string in 'HH:MM:SS' format

B The current date as a string in 'YYYY-MM-DD' format

C The current date and time as a datetime value

D The current Unix timestamp as an integer

💡 Hint

CURTIME() returns only the time part.

CURTIME() returns the current time as a string like '14:30:00'.

🧠 Conceptual

advanced

Difference between NOW() and CURDATE()

Which statement correctly describes the difference between NOW() and CURDATE() in MySQL?

A NOW() returns current date and time; CURDATE() returns only the current date

B NOW() returns only the current time; CURDATE() returns current date and time

C NOW() returns Unix timestamp; CURDATE() returns date as string

D NOW() returns only the current date; CURDATE() returns only the current time

💡 Hint

Think about what each function returns: date, time, or both.

NOW() returns both date and time, while CURDATE() returns only the date part.

📝 Syntax

expert

Which query will cause an error?

Identify which of the following queries will cause a syntax error in MySQL.

A SELECT NOW();

B SELECT CURDATE();

C SELECT CURTIME();

D SELECT NOW(5);

💡 Hint

Check if NOW() accepts any arguments.

NOW() does not accept any arguments; passing (5) causes a syntax error.

Practice

1. What does the MySQL function NOW() return?

easy

A. Only the current date

B. The current date and time

C. Only the current time

D. The current year

Solution

1. Step 1: Understand the function purpose

   NOW() is designed to return both date and time together.

2. Step 2: Compare with other functions

   CURDATE() returns only date, CURTIME() returns only time, so NOW() returns both.

3. Final Answer:

   The current date and time -> Option B

4. Quick Check:

   NOW() = current date + time [OK]

Hint: NOW() gives date and time together [OK]

Common Mistakes:

• Confusing NOW() with CURDATE()
• Thinking NOW() returns only time
• Assuming NOW() returns only year

2. Which of the following is the correct syntax to get only the current date in MySQL?

easy

A. SELECT CURDATE();

B. SELECT NOW();

C. SELECT CURRENT_TIME();

D. SELECT CURTIME();

Solution

1. Step 1: Identify function for current date

   CURDATE() returns only the current date in MySQL.

2. Step 2: Check other options

   NOW() returns date and time, CURRENT_TIME() and CURTIME() return only time.

3. Final Answer:

   SELECT CURDATE(); -> Option A

4. Quick Check:

   CURDATE() = current date only [OK]

Hint: Use CURDATE() for date only [OK]

Common Mistakes:

• Using NOW() when only date is needed
• Confusing CURTIME() with CURDATE()
• Using CURRENT_TIME() for date

3. What will be the output of this query if run at exactly 2024-06-15 14:30:45?

SELECT NOW(), CURDATE(), CURTIME();

medium

A. '2024-06-15 00:00:00', '14:30:45', '2024-06-15'

B. '2024-06-15', '14:30:45', '2024-06-15 14:30:45'

C. '14:30:45', '2024-06-15 14:30:45', '2024-06-15'

D. '2024-06-15 14:30:45', '2024-06-15', '14:30:45'

Solution

1. Step 1: Understand each function output

   NOW() returns full date and time, CURDATE() returns date only, CURTIME() returns time only.

2. Step 2: Match given time values

   At 2024-06-15 14:30:45, NOW() = '2024-06-15 14:30:45', CURDATE() = '2024-06-15', CURTIME() = '14:30:45'.

3. Final Answer:

   '2024-06-15 14:30:45', '2024-06-15', '14:30:45' -> Option D

4. Quick Check:

   NOW() = full datetime, CURDATE() = date, CURTIME() = time [OK]

Hint: NOW() full, CURDATE() date, CURTIME() time [OK]

Common Mistakes:

• Mixing order of outputs
• Assuming CURTIME() returns date
• Confusing NOW() with CURDATE()

4. Identify the error in this query:

SELECT NOW, CURDATE(), CURTIME();

medium

A. NOW is missing parentheses

B. CURDATE() should be CURTIME()

C. CURTIME() is misspelled

D. No error, query is correct

Solution

1. Step 1: Check function syntax

   MySQL functions require parentheses even if no arguments are passed. NOW without () is invalid.

2. Step 2: Verify other functions

   CURDATE() and CURTIME() have correct syntax with parentheses.

3. Final Answer:

   NOW is missing parentheses -> Option A

4. Quick Check:

   Functions need () even if empty [OK]

Hint: Always use () with MySQL functions [OK]

Common Mistakes:

• Omitting parentheses for functions
• Assuming functions can be called without ()
• Thinking CURDATE() is incorrect

5. You want to insert the current date and time into a table's created_at column. Which query correctly uses MySQL functions to do this?

hard

A. INSERT INTO logs (created_at) VALUES (CURDATE());

B. INSERT INTO logs (created_at) VALUES (CURTIME());

C. INSERT INTO logs (created_at) VALUES (NOW());

D. INSERT INTO logs (created_at) VALUES ('CURDATE()');

Solution

1. Step 1: Understand the column data type

   created_at usually stores full date and time, so we need a function that returns both.

2. Step 2: Choose correct function

   NOW() returns current date and time, CURDATE() returns only date, CURTIME() only time, and quoting function names inserts strings, not values.

3. Final Answer:

   INSERT INTO logs (created_at) VALUES (NOW()); -> Option C

4. Quick Check:

   Use NOW() for full datetime insert [OK]

Hint: Use NOW() to insert full date and time [OK]

Common Mistakes:

• Using CURDATE() when time is needed
• Using CURTIME() when date is needed
• Inserting function name as string