Datetrunc - SQL

Introduction

Datetrunc is a function in SQL that is used to truncate the time portion of a datetime value to a specified precision. This is useful in cases where we want to group datetime values by hour, day, month, etc.

The Datetrunc function is available in various SQL platforms, such as Oracle, MySQL, Microsoft SQL Server, etc.

Syntax

The syntax of the Datetrunc function varies slightly depending on the SQL platform being used. However, the general syntax is as follows:

DATETRUNC(<precision>, <datetime>)

Where:

• Precision indicates the level of precision desired for the truncated datetime value (e.g. 'hour', 'day', 'month', etc.)
• Datetime is the datetime value to be truncated

Examples

Example 1: Truncating to Hour

Suppose we have a table containing datetime values for each transaction, and we want to group transaction counts by hour. We can use the Datetrunc function to truncate each datetime value to the nearest hour.

SELECT COUNT(*), DATETRUNC('hour', transaction_datetime) AS hour_truncated
FROM transactions
GROUP BY hour_truncated;

Example 2: Truncating to Day

Suppose we have a table containing datetime values for each sale, and we want to group sales by day. We can use the Datetrunc function to truncate each datetime value to the nearest day.

SELECT SUM(sale_amount), DATETRUNC('day', sale_datetime) AS day_truncated
FROM sales
GROUP BY day_truncated;

Conclusion

The Datetrunc function in SQL is a useful tool for truncating datetime values to a specified precision. This can simplify grouping and aggregation of datetime values in SQL queries.