Amazon Redshift will no longer support the creation of new Python UDFs starting Patch 198. Existing Python UDFs will continue to function until June 30, 2026. For more information, see the [ blog post ](https://amazonaws-china.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/). 

# DATE\_TRUNC function
<a name="r_DATE_TRUNC"></a>

The DATE\_TRUNC function truncates a timestamp expression or literal based on the date part that you specify, such as hour, day, or month. 

## Syntax
<a name="r_DATE_TRUNC-synopsis"></a>

```
DATE_TRUNC('datepart', timestamp)
```

## Arguments
<a name="r_DATE_TRUNC-arguments"></a>

 *datepart*   
The date part to which to truncate the timestamp value. The input *timestamp* is truncated to the precision of the input *datepart*. For example, `month` truncates to the first day of the month. Valid formats are as follows:   
+ microsecond, microseconds
+ millisecond, milliseconds
+ second, seconds
+ minute, minutes
+ hour, hours
+ day, days
+ week, weeks
+ month, months
+ quarter, quarters
+ year, years
+ decade, decades
+ century, centuries
+ millennium, millennia
For more information about abbreviations of some formats, see [Date parts for date or timestamp functions](r_Dateparts_for_datetime_functions.md)

 *timestamp*   
A timestamp column or an expression that implicitly converts to a timestamp.

## Return type
<a name="r_DATE_TRUNC-return-type"></a>

TIMESTAMP

## Examples
<a name="r_DATE_TRUNC-example"></a>

Truncate the input timestamp to the second.

```
SELECT DATE_TRUNC('second', TIMESTAMP '20200430 04:05:06.789');
date_trunc
2020-04-30 04:05:06
```

Truncate the input timestamp to the minute.

```
SELECT DATE_TRUNC('minute', TIMESTAMP '20200430 04:05:06.789');
date_trunc
2020-04-30 04:05:00
```

Truncate the input timestamp to the hour.

```
SELECT DATE_TRUNC('hour', TIMESTAMP '20200430 04:05:06.789');
date_trunc
2020-04-30 04:00:00
```

Truncate the input timestamp to the day.

```
SELECT DATE_TRUNC('day', TIMESTAMP '20200430 04:05:06.789');
date_trunc
2020-04-30 00:00:00
```

Truncate the input timestamp to the first day of a month.

```
SELECT DATE_TRUNC('month', TIMESTAMP '20200430 04:05:06.789');
date_trunc
2020-04-01 00:00:00
```

Truncate the input timestamp to the first day of a quarter.

```
SELECT DATE_TRUNC('quarter', TIMESTAMP '20200430 04:05:06.789');
date_trunc
2020-04-01 00:00:00
```

Truncate the input timestamp to the first day of a year.

```
SELECT DATE_TRUNC('year', TIMESTAMP '20200430 04:05:06.789');
date_trunc
2020-01-01 00:00:00
```

Truncate the input timestamp to the first day of a century.

```
SELECT DATE_TRUNC('millennium', TIMESTAMP '20200430 04:05:06.789');
date_trunc
2001-01-01 00:00:00
```

Truncate the input timestamp to the Monday of a week.

```
select date_trunc('week', TIMESTAMP '20220430 04:05:06.789');
date_trunc
2022-04-25 00:00:00
```

In the following example, the DATE\_TRUNC function uses the 'week' date part to return the date for the Monday of each week. 

```
select date_trunc('week', saletime), sum(pricepaid) from sales where
saletime like '2008-09%' group by date_trunc('week', saletime) order by 1;

date_trunc  |    sum
------------+-------------
2008-09-01  | 2474899
2008-09-08  | 2412354
2008-09-15  | 2364707
2008-09-22  | 2359351
2008-09-29  |  705249
```