Re: TABLESAMPLE usage

you can accomplish this with row_number():

WITH data_cte as (
    SELECT
        id,
        clock_timestamp() as ctimestamp
    FROM generate_series(1,1000) as id
    )
SELECT
    *
FROM
    (SELECT
        id,
        ctimestamp,
        row_number() OVER (ORDER BY ctimestamp) as rownum
    FROM data_cte
    ) as data_withrownumbers
WHERE
    rownum%100=1;