How to use MySQL's FLOOR function to round down

How to use MySQL's FLOOR function to round down

In MySQL, the FLOOR function is used to round down. The FLOOR function is a very useful tool if you need to round down a floating point number or a number with a decimal point to the nearest integer. This article will introduce how to use MySQL's FLOOR function and provide some practical example code.

First, let us understand the syntax of the FLOOR function. The syntax of the FLOOR function is as follows:

FLOOR(x)

Among them, x represents the number to be rounded down. The FLOOR function will return the largest integer not greater than x. Here are some examples of using the FLOOR function:

-- Example 1: Round down an integer
SELECT FLOOR(5.6); -- The output result is 5

-- Example 2 : Round down a floating-point number
SELECT FLOOR(3.14); -- The output result is 3

-- Example 3: Round down a negative number
SELECT FLOOR(-2.5); -- The output result is -3

-- Example 4: Round down the decimal part
SELECT FLOOR(9.99); -- The output result is 9

Through the above example, you can see The use of the FLOOR function is very simple. It only takes one argument, the number to round down.

In practical applications, the FLOOR function can be used in various scenarios. The following are some common usage cases:

1. Calculate the sales quantity of an item
   Suppose you have a product sales table, which contains the sales quantity of each item, but the sales quantity may be a floating point number . In order to get an accurate sales quantity, you need to use the FLOOR function to round down the sales quantity to an integer.

Sample code:

SELECT product_id, FLOOR(sales_quantity) AS rounded_sales_quantity
FROM sales_table;

2. Calculate average grade
   Assume you There is a student performance table that contains the grades of each student. To calculate a student's grade point average, you need to use the FLOOR function to round the average grade down to an integer.

Sample code:

SELECT student_id, FLOOR(AVG(score)) AS rounded_average_score
FROM score_table
GROUP BY student_id;

3. Calculate the total amount of an order
   Suppose you have an order table that contains the total amount of each order. In order to calculate the total amount of the order, you need to use the FLOOR function to round down the total amount to an integer.

Sample code:

SELECT order_id, FLOOR(total_amount) AS rounded_total_amount
FROM order_table;

To sum up, MySQL’s FLOOR function is a Very useful tool for rounding down. Whether it is a floating point number or a number with a decimal point, the FLOOR function can help you convert it to the nearest integer. This facilitates a variety of calculations, from item sales quantities to performance calculations to order totals. By using the FLOOR function flexibly, you can better process and analyze data.

I hope this article can help you better understand and apply MySQL's FLOOR function. I wish you success in database querying and data analysis!

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