The ROUND() function is used to round a numeric field to the number of decimals specified.
Note: Many database systems do rounding differently than you might expect. When rounding a number with a fractional part to an integer, our school teachers told us to round .1 through .4 DOWN to the next lower integer, and .5 through .9 UP to the next higher integer. But if all the digits 1 through 9 are equally likely, this introduces a slight bias towards infinity, since we always round .5 up. Many database systems have adopted the IEEE 754 standard for arithmetic operations, according to which the default rounding behavior is "round half to even." In this scheme, .5 is rounded to the nearest even integer. So, both 11.5 and 12.5 would be rounded to 12.
|column_name||Required. The field to round.|
|decimals||Required. Specifies the number of decimals to be returned.|
In this tutorial we will use the well-known Northwind sample database.
Below is a selection from the "Products" table:
|1||Chais||1||1||10 boxes x 20 bags||18|
|2||Chang||1||1||24 - 12 oz bottles||19|
|3||Aniseed Syrup||1||2||12 - 550 ml bottles||10|
|4||Chef Anton's Cajun Seasoning||2||2||48 - 6 oz jars||21.35|
|5||Chef Anton's Gumbo Mix||2||2||36 boxes||25|
The following SQL statement selects the product name and rounds the price in the "Products" table: