NOW, CURDATE, CURTIME in MySQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the MySQL function NOW() return?

NOW() returns the current date and time in the format YYYY-MM-DD HH:MM:SS.

beginner

How is CURDATE() different from NOW() in MySQL?

CURDATE() returns only the current date (YYYY-MM-DD), while NOW() returns both date and time.

beginner

What does the MySQL function CURTIME() return?

CURTIME() returns the current time in the format HH:MM:SS without the date.

beginner

Write a MySQL query to get the current date and time using NOW().

SELECT NOW();

This query returns the current date and time.

beginner

If you want to store only the current time in a column, which function would you use?

You would use CURTIME() to get the current time only.

Which MySQL function returns the current date and time together?

A CURRENT_TIME()

B CURDATE()

C NOW()

D CURTIME()

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

What format does CURDATE() return?

A YYYY-MM-DD

B HH:MM:SS

C YYYY-MM-DD HH:MM:SS

D MM-DD-YYYY

CURDATE() returns the date in YYYY-MM-DD format.

Which function would you use to get only the current time in MySQL?

A NOW()

B CURTIME()

C CURDATE()

D CURRENT_DATE()

CURTIME() returns only the current time.

What does the query SELECT NOW(); return?

A Current year only

B Current time only

C Current date only

D Current date and time

NOW() returns the current date and time.

If you want to compare only the date part of a datetime column, which function helps you get the current date?

A CURDATE()

B CURTIME()

C NOW()

D TIME()

CURDATE() returns the current date, useful for date-only comparisons.

Explain the difference between NOW(), CURDATE(), and CURTIME() in MySQL.

Think about what part of the date/time each function returns.

Write a simple MySQL query to get the current time and explain what it returns.

Focus on the function that returns time only.

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