How to Extract the Date (yyyy/mm/dd) from Timestamps in PostgreSQL?

Extracting Date (yyyy/mm/dd) from Timestamps in PostgreSQL

When working with timestamps in PostgreSQL, there may arise a need to extract the date component for further processing. This article explores several approaches to achieving this conversion.

Casting to Date

The simplest method involves casting the timestamp to a date using the ::date suffix. This eliminates the time portion, leaving only the date value. For instance, let's consider a timestamp:

'2010-01-01 12:00:00'::timestamp

By casting it to a date, we obtain:

'2010-01-01 12:00:00'::timestamp::date

The result is '2010-01-01,' which matches the expected format.

Using date_trunc Function

Another versatile option is to employ the date_trunc function. This function truncates a date or timestamp value to the specified time interval. To extract the date, we can use:

date_trunc('day', timestamp)

Unlike casting, date_trunc preserves the data type of the timestamp, including its time zone, if applicable.

To illustrate, consider the current timestamp:

now()

Applying date_trunc to it yields:

date_trunc('day', now())

The result is a timestamp with the time portion truncated to midnight, preserving the current date and time zone.

By leveraging the power of PostgreSQL's date handling capabilities, developers can effortlessly extract date components from timestamps, facilitating data manipulation and analysis tasks.

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