MySQL - Today Date

Hello, aspiring database enthusiasts! Today, we're going to dive into the exciting world of dates in MySQL. As your friendly neighborhood computer science teacher, I'm here to guide you through the ins and outs of working with today's date in MySQL. Don't worry if you've never written a line of code before – we'll start from the very beginning and work our way up. So, grab your virtual notepads, and let's get started!

MySQL Today's Date

What is Today's Date in MySQL?

In MySQL, "today's date" refers to the current date according to the database server's system clock. It's like asking your computer, "Hey, what day is it today?" and getting an accurate answer. This might seem simple, but it's incredibly useful in many database applications.

How to Get Today's Date

MySQL provides several functions to retrieve the current date. Let's look at the most common ones:

Function	Description	Example Output
CURDATE()	Returns the current date	2023-05-15
CURRENT_DATE()	Synonym for CURDATE()	2023-05-15
CURRENT_DATE	Synonym for CURDATE()	2023-05-15
NOW()	Returns the current date and time	2023-05-15 14:30:00

Let's try these out! Here's a simple query to get today's date:

SELECT CURDATE() AS Today;

This will return something like:

+------------+
| Today      |
+------------+
| 2023-05-15 |
+------------+

Cool, right? It's like having a built-in calendar in your database!

Formatting the Date

Sometimes, you might want to display the date in a different format. MySQL's got you covered with the DATE_FORMAT() function. Here's how you can use it:

SELECT DATE_FORMAT(CURDATE(), '%W, %M %d, %Y') AS Formatted_Date;

This might return:

+-------------------------+
| Formatted_Date          |
+-------------------------+
| Monday, May 15, 2023    |
+-------------------------+

The '%W', '%M', '%d', and '%Y' are format specifiers that tell MySQL how to display the date. It's like giving instructions to a friend on how to write the date – "First the day of the week, then the month, then the day number, and finally the year."

Inserting Date Values in a Table

Now that we know how to get today's date, let's see how we can use it in a real-world scenario. Imagine we're building a library database, and we want to keep track of when books are borrowed.

First, let's create a simple table:

CREATE TABLE book_loans (
    id INT AUTO_INCREMENT PRIMARY KEY,
    book_title VARCHAR(100),
    borrow_date DATE
);

This creates a table with three columns: an ID, the book title, and the date it was borrowed. Now, let's insert a record using today's date:

INSERT INTO book_loans (book_title, borrow_date)
VALUES ('The MySQL Adventurer', CURDATE());

This inserts a new record with the current date as the borrow_date. It's like writing in a logbook, "Someone borrowed 'The MySQL Adventurer' today."

We can check our work by selecting from the table:

SELECT * FROM book_loans;

You might see something like:

+----+----------------------+------------+
| id | book_title           | borrow_date|
+----+----------------------+------------+
|  1 | The MySQL Adventurer | 2023-05-15 |
+----+----------------------+------------+

Today Date Using Client Program

When you're working with MySQL through a client program (like the MySQL command-line client), you can also use the NOW() function to get the current date and time. Here's a quick example:

SELECT NOW() AS Current_DateTime;

This will give you something like:

+---------------------+
| Current_DateTime    |
+---------------------+
| 2023-05-15 15:30:45 |
+---------------------+

It's like asking your wristwatch for both the date and time!

Practical Application: Age Calculator

Let's put our knowledge to use with a practical example. Suppose we want to calculate someone's age based on their birth date. We can use the DATEDIFF() function along with CURDATE():

SELECT 
    'John Doe' AS Name,
    '1990-05-15' AS Birthdate,
    FLOOR(DATEDIFF(CURDATE(), '1990-05-15') / 365) AS Age;

This query might return:

+----------+------------+------+
| Name     | Birthdate  | Age  |
+----------+------------+------+
| John Doe | 1990-05-15 |   33 |
+----------+------------+------+

Here, we're calculating the number of days between the birthdate and today, then dividing by 365 to get the age in years. It's like counting the candles on a birthday cake, but much faster!

Conclusion

And there you have it, folks! We've journeyed through the land of dates in MySQL, from simply getting today's date to using it in practical scenarios. Remember, working with dates might seem tricky at first, but with practice, it'll become second nature.

As we wrap up, here's a little database humor for you: Why did the database admin leave his wife? He wanted to start a new relationship! (Ba dum tss!)

Keep practicing, stay curious, and before you know it, you'll be handling dates in MySQL like a pro. Until next time, happy coding!

Credits: Image by storyset