DB-Fiddle Expected Result In the results I want to display the quantity for all dates except for the first row. I know in the example above I can do this with a simple WHERE-condition like this: However, it is neither guaranteed that the first time_stamp will be always 2020-01-14 nor that the MIN(2020-01-14) is always in the first row. Therefore,

First row of results should never be displayed

CREATE TABLE logistics (
    id SERIAL PRIMARY KEY,
    time_stamp DATE,
    quantity INT
);

INSERT INTO logistics
(time_stamp, quantity)
VALUES 
('2020-01-14', '100'),
('2020-01-15', '400'),
('2020-01-16', '530'),
('2020-01-17', '500');

Expected Result

time_stamp  |  quantity  |
------------|------------|------
2020-01-15  |    400     |
2020-01-16  |    530     |
2020-01-17  |    500     |

In the results I want to display the quantity for all dates except for the first row.
I know in the example above I can do this with a simple WHERE-condition like this:

SELECT
l.time_stamp AS time_stamp, 
SUM(quantity) AS quantity
FROM logistics l
WHERE time_stamp <> '2020-01-14'
GROUP BY 1
ORDER BY 1;

However, it is neither guaranteed
that the first time_stamp will be always 2020-01-14
nor that the MIN(2020-01-14) is always in the first row.

Therefore, I am wondering how I have to modify the query to always not-display the first row of the results?

Answer

Since this is Postgresql, you can use the OFFSET clause.

https://www.postgresql.org/docs/current/queries-limit.html

SELECT
l.time_stamp AS time_stamp, 
SUM(quantity) AS quantity
FROM logistics l
GROUP BY 1
ORDER BY 1
OFFSET 1;

Advertisement

Answer