What Data Type Does the Datetrunc Function Return?
The DATETRUNC function is a powerful tool in SQL that allows you to truncate or round down a date value to a specified level of precision. It is commonly used when you want to ignore the time portion of a datetime value and focus only on the date part.
Using the DATETRUNC Function
To use the DATETRUNC function, you need to provide two arguments:
- The first argument is the precision level at which you want to truncate the date. This can be one of several options: ‘year’, ‘quarter’, ‘month’, ‘week’, ‘day’, ‘hour’, ‘minute’, or ‘second’.
- The second argument is the date or datetime value that you want to truncate.
The DATETRUNC function will then return a new value with the specified precision level, where any parts beyond that level are set to zero or ignored.
Suppose we have a datetime value ‘2021-06-15 14:30:45’. Let’s see what happens when we apply different precision levels with the DATETRUNC function:
- DATETRUNC(‘year’, ‘2021-06-15 14:30:45’): This will return ‘2021-01-01’. It ignores all parts beyond the year and sets them to zero.
- DATETRUNC(‘month’, ‘2021-06-15 14:30:45’): This will return ‘2021-06-01’.
It ignores all parts beyond the month and sets them to zero.
- DATETRUNC(‘day’, ‘2021-06-15 14:30:45’): This will return ‘2021-06-15’. It ignores all parts beyond the day and sets them to zero.
As you can see, the DATETRUNC function returns a date value with the specified precision level. The data type of the returned value is always a date, regardless of whether the input was a date or datetime value.
The DATETRUNC function is a valuable tool for manipulating date and datetime values in SQL. It allows you to truncate or round down a date value to a specified precision level, ignoring any parts beyond that level. The returned value is always of type date, regardless of the input type.
Now that you understand what data type the DATETRUNC function returns, you can confidently use it in your SQL queries to effectively manipulate dates and times.