[Edit] SQL: ROUND()

content/sql/concepts/commands/terms/round/round.md

@@ -1,35 +1,90 @@
 ---
-Title: 'ROUND'
-Description: 'Rounds a value to the nearest integer or to a specific number of decimals if an optional value is provided.'
+Title: 'ROUND()'
+Description: 'Rounds a value to the nearest integer or to a specific number of decimals.'
 Subjects:
   - 'Computer Science'
   - 'Data Science'
 Tags:
   - 'Data Types'
   - 'Integers'
   - 'Numbers'
+  - 'Values'
 CatalogContent:
   - 'learn-sql'
   - 'paths/analyze-data-with-sql'
 ---
 
-The **`ROUND`** command rounds a value to the nearest integer or to a specific number of decimals if an optional value is provided.
+In SQL, the **`ROUND()`** function rounds a value to the nearest integer or to a specific number of decimals. It's a powerful function that helps ensure consistency and accuracy in the output data.
 
 ## Syntax
 
 ```pseudo
 ROUND(value, decimal_places)
 ```
 
-If the optional `decimal_places` parameter is omitted, then the `value` is rounded with zero decimals.
+**Parameters:**
 
-## Example
+- `value`: The value to be rounded.
+- `decimal_places` (Optional): The total number of decimal places to round to. If omitted, the default is `0` (round to the nearest whole number).
 
-The example below assumes there is a `grades` table with a column `test_scores` with values for all the exams administered in a semester, rounded to two decimal places:
+## Example 1: Basic Rounding Using `ROUND()`
+
+This example utilizes the `ROUND()` function to round a floating-point number to two decimal places:
+
+```sql
+SELECT ROUND(123.4567, 2) AS RoundedValue;
+```
+
+Here is the output:
+
+```shell
+RoundedValue
+-------------
+123.46
+```
+
+## Example 2: Rounding to Whole Numbers Using `ROUND()`
+
+This example utilizes the `ROUND()` function without specifying decimal places to round a floating-point number to the nearest whole number:
 
 ```sql
-SELECT names,
-ROUND(AVG(test_scores), 2) AS semester_avg
-FROM grades
-GROUP BY names;
+SELECT ROUND(98.7) AS RoundedValue;
 ```
+
+Here is the output:
+
+```shell
+RoundedValue
+-------------
+99
+```
+
+## Example 3: Rounding to Negative Decimal Places Using `ROUND()`
+
+This example utilizes the `ROUND()` function to round a floating-point number to the left of the decimal point:
+
+```sql
+SELECT ROUND(12345.67, -2) AS RoundedValue;
+```
+
+Here is the output:
+
+```shell
+RoundedValue
+-------------
+12300
+```
+
+## Frequently Asked Questions
+
+### 1. Does `ROUND()` always round up?
+
+No. `ROUND()` follows the standard rounding rule: it rounds up if the next digit is 5 or more and down otherwise.
+
+### 2. Is `ROUND()` supported in all SQL databases?
+
+Yes, `ROUND()` is supported in all SQL databases. However, the syntax and behavior may differ slightly.
+
+### 3. What’s the difference between `ROUND()` and `TRUNC()`?
+
+`ROUND()` adjusts values based on rounding rules, while `TRUNC()` simply cuts off digits without rounding.