ROUND Date

The ROUND function in Oracle is used to round a date or timestamp to a specified unit of time. This is useful when you need to adjust the date to the nearest specified interval, such as rounding to the nearest day, month, or year.

 

Syntax:

ROUND(date_value, format)

• date_value: The date or timestamp value that you want to round.
• format: The unit to which you want to round the date (e.g., day, month, year, hour). If you omit the format, the date is rounded to the nearest day by default.

 

Return Type:

• The return type of ROUND is a date value, which is the rounded result.

 

Common format Values:

The format specifies the unit to which the date should be rounded. Some common format options include:

• 'YEAR': Rounds to the nearest year.
• 'MONTH': Rounds to the nearest month.
• 'DAY': Rounds to the nearest day.
• 'HH' (or 'HH24', 'HH12'): Rounds to the nearest hour.
• 'MI': Rounds to the nearest minute.
• 'SS': Rounds to the nearest second.
• 'Q': Rounds to the nearest quarter (1st, 2nd, 3rd, or 4th quarter of the year).

 

Default Behavior:

If no format is provided, the function rounds to the nearest day by default.

 

Examples of Using ROUND with Different Formats:

1. Round to the Nearest Year:

Rounds a given date to the nearest year.

SELECT ROUND(DATE '2025-08-15', 'YEAR') FROM dual;

-- Result: 01-JAN-2025

Explanation: The date 2025-08-15 is rounded to the nearest year, which is 01-JAN-2025 because it's closer to the start of the year.

2. Round to the Nearest Month:

Rounds a given date to the nearest month.

SELECT ROUND(DATE '2025-08-15', 'MONTH') FROM dual;

-- Result: 01-AUG-2025

Explanation: The date 2025-08-15 is rounded to the nearest month, which is 01-AUG-2025.

3. Round to the Nearest Day:

Rounds a date to the nearest day (default behavior).

SELECT ROUND(DATE '2025-08-15', 'DAY') FROM dual;

-- Result: 15-AUG-2025

Explanation: In this case, 2025-08-15 is already on a day, so the result remains the same.

4. Round to the Nearest Hour:

Rounds a date or timestamp to the nearest hour.

SELECT ROUND(TIMESTAMP '2025-08-15 13:40:00', 'HH') FROM dual;

-- Result: 01-AUG-2025 14:00:00

Explanation: The timestamp 2025-08-15 13:40:00 is rounded to the nearest hour, which is 14:00:00.

5. Round to the Nearest Minute:

Rounds a timestamp to the nearest minute.

SELECT ROUND(TIMESTAMP '2025-08-15 13:42:30', 'MI') FROM dual;

-- Result: 15-AUG-2025 13:43:00

Explanation: The timestamp 2025-08-15 13:42:30 is rounded to the nearest minute, which is 13:43:00.

6. Round to the Nearest Quarter:

Rounds a date to the nearest quarter of the year (1st, 2nd, 3rd, or 4th quarter).

SELECT ROUND(DATE '2025-08-15', 'Q') FROM dual;

-- Result: 01-JUL-2025

Explanation: The date 2025-08-15 is rounded to the nearest quarter, which is 01-JUL-2025 (the start of the third quarter).

7. Round to the Nearest Second:

Rounds a timestamp to the nearest second.

SELECT ROUND(TIMESTAMP '2025-08-15 13:42:30.567', 'SS') FROM dual;

-- Result: 15-AUG-2025 13:42:31

Explanation: The timestamp 2025-08-15 13:42:30.567 is rounded to the nearest second, which is 13:42:31.

 

Additional Notes:

1.     Rounding Direction:

• Oracle rounds in a way that depends on the time part:
• For example, rounding to the nearest hour will round any time before the half-hour mark down (e.g., 13:20 would round to 13:00), while times after the half-hour mark will round up (e.g., 13:40 would round to 14:00).

2.     Date vs Timestamp:

• The ROUND function can be used on both DATE and TIMESTAMP data types. The behavior is similar for both, but TIMESTAMP values allow for finer precision (e.g., milliseconds) when rounding.

3.     Null Values:

• If the input date or timestamp is NULL, the ROUND function will return NULL as the result.

4.     Rounding to Different Date Parts:

• The ROUND function is very versatile and allows for rounding to any significant date part (year, month, day, hour, minute, etc.). Be mindful of which part you need, as rounding to a higher unit (e.g., year) may result in a large change in the date.

5.     Impact on Time Zones:

• When rounding TIMESTAMP WITH TIME ZONE values, the time zone part is unaffected. Only the date and time components are rounded based on the specified unit.

 

Use Cases:

1.     Standardizing Dates:

• When working with time series data, you may want to round dates to a consistent level of granularity (e.g., rounding all timestamps to the nearest month or quarter for reporting).

2.     Financial and Business Reporting:

• You might round dates to the start of the quarter or fiscal year for reporting financial data that is aggregated on a quarterly or yearly basis.

3.     Scheduling and Calendar Applications:

• In scheduling applications, rounding to the nearest hour or minute is useful to standardize times for events, meetings, or deadlines.

4.     Cleaning and Aggregating Data:

• Rounding dates can be helpful when cleaning up data for aggregation, particularly when you want to group events by month, quarter, or year.

 

Summary:

The ROUND function in Oracle provides a way to round dates or timestamps to a specified unit of time, such as year, month, day, hour, minute, second, or quarter. It's a powerful tool for standardizing date values for analysis and reporting. By understanding the various format options and their behavior, you can effectively manage time-based data for your application needs.