How to calculate DATE Difference in PostgreSQL?

PostgresqlDatediff

Postgresql Problem Overview

Here I need to calculate the difference of the two dates in the PostgreSQL.

In SQL Server: Like we do in SQL Server its much easier.

DATEDIFF(Day, MIN(joindate), MAX(joindate)) AS DateDifference;

My Try: I am trying using the following script:

(Max(joindate) - Min(joindate)) as DateDifference;

Question:

  • Is my method correct?

  • Is there any function in PostgreSQL to calculate this?

Postgresql Solutions

Solution 1 - Postgresql

Your calculation is correct for DATE types, but if your values are timestamps, you should probably use EXTRACT (or DATE_PART) to be sure to get only the difference in full days;

EXTRACT(DAY FROM MAX(joindate)-MIN(joindate)) AS DateDifference

http://sqlfiddle.com/#!15/0d359/2">An SQLfiddle to test with. Note the timestamp difference being 1 second less than 2 full days.

Solution 2 - Postgresql

CAST both fields to datatype DATE and you can use a minus:

(CAST(MAX(joindate) AS date) - CAST(MIN(joindate) AS date)) as DateDifference

Test case:

SELECT	(CAST(MAX(joindate) AS date) - CAST(MIN(joindate) AS date)) as DateDifference
FROM 
	generate_series('2014-01-01'::timestamp, '2014-02-01'::timestamp, interval '1 hour') g(joindate);

Result: 31

Or create a function datediff():

CREATE OR REPLACE FUNCTION datediff(timestamp, timestamp) 
RETURNS int 
LANGUAGE sql 
AS
$$
	SELECT CAST($1 AS date) - CAST($2 AS date) as DateDifference
$$;

Solution 3 - Postgresql

a simple way would be to cast the dates into timestamps and take their difference and then extract the DAY part.

if you want real difference

select extract(day from 'DATE_A'::timestamp - 'DATE_B'::timestamp);

if you want absolute difference

select abs(extract(day from 'DATE_A'::timestamp - 'DATE_B'::timestamp));

Solution 4 - Postgresql

This is how I usually do it. A simple number of days perspective of B minus A.

DATE_PART('day', MAX(joindate) - MIN(joindate)) as date_diff

Solution 5 - Postgresql

This is not a direct answer to OP's question, however, this is the answer I was looking for when my search brought me to this thread.

For someone who wants to create a human-readable string that denotes the difference between two dates, consider using AGE().

 AGE(table.end_date, table.start_date)

It produces results that looks like these:

0:00:27

3 days 22:06:39.833264
4 days 01:12:39.473559
20 days 17:53:20.23287
23 days 21:01:15.150703

1 mon 19 days 01:52:24.262275
2 mons 17 days 05:04:12.277099
2 mons 17 days 04:59:21.618069
Categories
Recommended Postgresql Solutions
Recommended Datediff Solutions

Previous Solution:

What exactly is a merge conflict?

GitGit Merge

Next Solution:

Catching Errors in JavaScript Promises with a First Level try ... catch

Javascriptnode.jsPromiseBluebird

Attributions

All content for this solution is sourced from the original question on Stackoverflow.

The content on this page is licensed under the Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license.

Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionSarfaraz MakandarView Question on Stackoverflow
Solution 1 - PostgresqlJoachim IsakssonView Answer on Stackoverflow
Solution 2 - PostgresqlFrank HeikensView Answer on Stackoverflow
Solution 3 - Postgresqlzubair-0View Answer on Stackoverflow
Solution 4 - PostgresqlanoraqView Answer on Stackoverflow
Solution 5 - PostgresqlClint GossettView Answer on Stackoverflow