In SQL Server, the ROUND function is used to round a numeric value to a specific length or precision. It can be used to round up or down to the nearest integer or specified decimal place. The function takes two arguments: the number to be rounded and the number of decimal places to round to.
The syntax for the ROUND function is as follows:
ROUND(number, decimal_places)
In this article, we will explore the ROUND function in SQL Server and provide example code for rounding numbers from round 5 up to 1 decimal place.
ROUND 5 UP TO 1 DECIMAL PLACE
Suppose we have the following table in our database:
ID  Price
1  12.45
2  7.89
3  23.50
We can use the ROUND function to round the Price column to one decimal place. The code for this would be:
SELECT ID, ROUND(Price, 1) AS Rounded_Price
FROM Table1
The result set would be:
ID  Rounded_Price
1  12.5
2  7.9
3  23.5
As we can see, the ROUND function has rounded the values in the Price column to one decimal place. In addition, it has rounded up any numbers that end in 5 to the nearest even number.
For example, 12.45 has been rounded up to 12.5 and 23.50 has been rounded down to 23.5. However, 7.89 has not been rounded up to 7.9 because the digit after 9 is less than 5.
THE ROUND FUNCTION IN DEPTH
The ROUND function in SQL Server is a powerful tool that can be used to round numbers to a specific length or precision. Let's take a closer look at how it works.
The first argument to the ROUND function is the number to be rounded. This number can be a decimal or integer value. The second argument is the number of decimal places to round to. This argument can be positive or negative.
If the number of decimal places is positive, the function rounds the number to the specified number of decimal places. For example, if we want to round the number 3.14159 to two decimal places, we would use the following code:
SELECT ROUND(3.14159, 2)
The result would be 3.14.
If the number of decimal places is negative, the function rounds the number to the left of the decimal point. For example, if we want to round the number 12345.6789 to the nearest thousand, we would use the following code:
SELECT ROUND(12345.6789, 3)
The result would be 12000.
In addition to rounding numbers to a specific number of decimal places, the ROUND function can also be used to round numbers up or down to the nearest integer. This is done by specifying a second argument of 0. For example, if we want to round the number 3.14159 to the nearest integer, we would use the following code:
SELECT ROUND(3.14159, 0)
The result would be 3.
CONCLUSION
In conclusion, the ROUND function in SQL Server is a powerful tool that can be used to round numbers to a specific length or precision. It can be used to round up or down to the nearest integer or specified decimal place. Understanding how to use the ROUND function is essential for any developer working with SQL Server.
I can write more about the previous topic, "ROUND 5 UP TO 1 DECIMAL PLACE" and expand on how the ROUND function works in SQL Server.
ROUNDING WITH THE ROUND FUNCTION
The ROUND function in SQL Server follows standard rounding rules when rounding numbers. When rounding a number, the function looks at the value of the digit in the decimal place that we want to round to (the round digit). If the value of the round digit is less than 5, the function rounds down. If the value of the round digit is 5 or greater, the function rounds up.
For example, if we want to round the number 2.4 to one decimal place, the function looks at the value of the digit in the tenths place (the round digit), which is 4. Since 4 is less than 5, the function rounds 2.4 down to 2.3. Conversely, if we want to round the number 2.6 to one decimal place, the function looks at the value of the digit in the tenths place, which is 6. Since 6 is greater than or equal to 5, the function rounds 2.6 up to 2.7.
In addition to standard rounding rules, the ROUND function in SQL Server also follows the "round half to even" rule when rounding numbers that end in 5. This means that, when rounding a number that ends in 5, if the digit before the 5 is even, the function rounds down. If the digit before the 5 is odd, the function rounds up. For example, if we want to round the number 1.25 to one decimal place, the function looks at the value of the digit in the tenths place, which is 5. Since the digit before the 5 (2) is even, the function rounds 1.25 down to 1.2.
ROUNDING EXAMPLES
Let's look at some examples of how to use the ROUND function with different integers and decimal places:
 To round the number 1.345 to two decimal places, we would use the following code: SELECT ROUND(1.345, 2) The result would be 1.35, since the round digit (the digit in the hundredths place) is 5, which rounds up.
 To round the number 2.59 to one decimal place, we would use the following code: SELECT ROUND(2.59, 1) The result would be 2.6, since the round digit (the digit in the tenths place) is 9, which rounds up.
 To round the number 10 to the nearest ten, we would use the following code: SELECT ROUND(10, 1) The result would be 10, since there are no digits to the right of the tens place to round.
In conclusion, the ROUND function in SQL Server is useful for rounding numbers to a specific length or precision. Understanding how the function works can help you write more accurate and efficient SQL queries.
Popular questions

What is the purpose of the ROUND function in SQL Server?
Answer: The ROUND function in SQL Server is used to round a numeric value to a specific length or precision. It rounds a number up or down to the nearest integer or specified decimal place. 
How is the ROUND function used to round a number to one decimal place?
Answer: The ROUND function is used with two arguments of the number to be rounded and the number of decimal places to round to. For example, SELECT ROUND(3.14159, 1) would round the value 3.14159 to 1 decimal place, resulting in 3.1. 
What happens when the digit after 5 is 0 in the ROUND function in SQL Server?
Answer: If the digit after 5 is 0, the ROUND function will not round up. Instead, it will round down. For example, rounding 2.50 to 1 decimal place will result in 2.5 since the digit after 5 is 0. 
What is the syntax of the ROUND function in SQL Server?
Answer: The ROUND function requires two arguments, the number to be rounded and the number of decimal places to round to. The syntax is as follows: ROUND(number, decimal_places). 
What is the result of rounding 6.5 to the nearest integer using the ROUND function?
Answer: Rounding 6.5 to the nearest integer using the ROUND function would result in 6. This is because the ROUND function follows standard rounding rules when rounding numbers and will round down if the value of the round digit is less than 5.
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