PostgreSQL date string to timestamp

In this comprehensive article, I’ll explain everything you need to know about converting a date string into PostgreSQL’s timestamp data type.

PostgreSQL date string to timestamp

Let’s explore the various methods to convert your string dates into proper timestamps.

Approach 1: Using TO_TIMESTAMP() Function

The most common and flexible approach is using PostgreSQL’s built-in TO_TIMESTAMP() function. This function converts a string to a timestamp based on a specified format.

Syntax

TO_TIMESTAMP(string_to_convert, format_mask)

The function takes two parameters:

• The string you want to convert
• A format pattern that tells PostgreSQL how to interpret the string

Example -1

We can execute the following query to convert the YYYYMMDD format.

SELECT TO_TIMESTAMP('20250620', 'YYYYMMDD');

After executing the above query, I got the expected output as shown in the screenshot below.

Example -2

We can execute the below query to convert with time components.

SELECT TO_TIMESTAMP('20201123043000', 'YYYYMMDDHH24MISS');

After executing the above query, I got the expected output as shown in the screenshot below.

Example-3

We can use the following query to convert to US format: MM/DD/YYYY.

SELECT TO_TIMESTAMP('05/20/2025', 'MM/DD/YYYY');

I got the expected output after executing the above query as shown in the screenshot below.

Example-4

We can also use the below query to convert with time: MM/DD/YYYY HH:MI:SS.

SELECT TO_TIMESTAMP('05/20/2025 15:30:45', 'MM/DD/YYYY HH24:MI:SS');

After executing the above query, I got the expected output as shown in the screenshot below.

Example-5

We can execute the below query to convert the US format with the month name: Month DD, YYYY.

SELECT TO_TIMESTAMP('May 20, 2025', 'Month DD, YYYY');

I got the expected output after executing the above query.

The format pattern uses special template patterns like:

• YYYY – 4-digit year
• MM – 2-digit month
• DD – 2-digit day
• HH24 – 24-hour format hours
• MI – minutes
• SS – seconds

Approach 2: Using CAST or Type Coercion

We can use the CAST operator or double-colon syntax for type coercion.

Example-1

We can use the CAST function with the query below.

SELECT CAST('2025-05-20' AS TIMESTAMP);

I got the expected output after executing the above query as shown in the screenshot below.

Example-2

Using the query below, we can use the double-colon syntax (PostgreSQL shorthand).

SELECT '2025-05-20'::TIMESTAMP;

I got the expected output as shown below.

Method 3: Using TO_DATE() and Then Converting

Sometimes, you might want to first convert to a date type and then to a timestamp, especially if you’re only concerned with the date portion initially, using the below query.

SELECT TO_DATE('05/20/2025', 'MM/DD/YYYY')::TIMESTAMP

After executing the above query, I got the expected output as shown in the screenshot below.

Format Pattern Reference Table

Here’s the table of the format patterns you can use with the TO_TIMESTAMP() function:

Pattern	Description	Example
YYYY	4-digit year	2025
YY	2-digit year	25
MM	Month number (01-12)	05
MON	Abbreviated month name	May
MONTH	Full month name	May
DD	Day of month (01-31)	20
HH	Hour (01-12)	10
HH24	Hour (00-23)	22
MI	Minute (00-59)	45
SS	Second (00-59)	30
MS	Millisecond	500
US	Microsecond	500000
TZ	Time zone abbreviation	EST
OF	Time zone offset	-05:00

Best Practices

Below are some best practices to follow:

1. Always be explicit about formats – Don’t rely on PostgreSQL guessing your date format correctly.
2. Use ISO format when possible – The YYYY-MM-DD format is internationally recognized and less prone to ambiguity.
3. Handle time zones appropriately – Be explicit about time zones, especially in applications serving users across different regions.
4. Validate before converting – When dealing with user input, validate the format before converting.

Conclusion

Converting date strings to timestamps in PostgreSQL is an essential skill you should know as a developer. With the TO_TIMESTAMP() function, type casting, and proper format patterns, you can achieve this using the information mentioned in this article.