ROUND Function in SQL Server: A Practical Guide

This guide will show you in detail how to use the SQL Server ROUND () function with syntax and examples to better visualize and capture functions better.

Describe

The ROUND function in SQL Server helps round numbers to a certain decimal place.

Syntax

To use the ROUND function in SQL Server, we use the following syntax:

 ROUND(number, decimal, operation) 

Parameters :

• number: number passed to round
• Decimal : The number of decimal places is rounded to. This value must be a positive or negative integer. If this parameter is omitted, the ROUND function will round the number to 0 decimal places.
• operation: parameter not required. The operation can be any other numeric value. When it is 0 (or omitted), the ROUND function will round the result into a decimal. If the operation is any value other than 0, the ROUND function will cut the result into a decimal.

Principle of rounding :

When you round the number, the system will check the number in position (decimal + 1):

• If the number is greater than 4, the number in the decimal position will add 1. The numbers at the back become 0
• If the number is less than 5, the number in the decimal position will remain the same. The numbers on the back become 0

For instance, we have a decimal number of 423.3241

• ROUND function can be used in later versions of SQL Server: SQL Server 2017, SQL Server 2016, SQL Server 2014, SQL Server 2012, SQL Server 2008 R2, SQL Server 2008, and SQL Server 2005.

For instance,

Take a look and explore some examples of ROUND functions in SQL Server.

Example 1: Round the numbers

 SELECT ROUND(125.315, 2); 
 Result: 125.320 (k?t qu? ???c làm tròn vì tham s? th? 3 b? b? qua) 
 
 SELECT ROUND(125.315, 2, 0); 
 Result: 125.320 (k?t qu? ???c làm tròn vì tham s? th? 3 là 0) 
 
 SELECT ROUND(125.315, 2, 1); 
 Result: 125.310 (k?t qu? b? c?t b?t vì tham s? th? 3 khác 0) 
 
 SELECT ROUND(125.315, 1); 
 Result: 125.300 (k?t qu? ???c làm tròn vì tham s? th? 3 b? b? qua) 
 
 SELECT ROUND(125.315, 0); 
 Result: 125.000 (k?t qu? ???c làm tròn vì tham s? th? 3 b? b? qua) 
 
 SELECT ROUND(125.315, -1); 
 Result: 130.000 (k?t qu? ???c làm tròn vì tham s? th? 3 b? b? qua) 
 
 SELECT ROUND(125.315, -2); 
 Result: 100.000 (k?t qu? ???c làm tròn vì tham s? th? 3 b? b? qua) 

Example 2: We have the following data table

1. Get the sub-column and rate of the website, rounding the ratio to the 2nd decimal place

 SELECT Chuyenmuccon, ROUND(Tyle, 2) AS Tylemoi 
 FROM Tipsmake; 
 
 Result: 
 Chuyenmuccon Tylemoi 
 SQL Server 74.63 
 Facebook 58.99 
 Python 36.22 
 JavaScript 42.68 
 Google Chrome 94.88 
 Instagram 82.16 

Next lesson: SIGN function in SQL Server