[SQL] Best way to select random rows PostgreSQL

I want a random selection of rows in PostgreSQL, I tried this:

select * from table where random() < 0.01;


But some other recommend this:

select * from table order by random() limit 1000;


I have a very large table with 500 Million rows, I want it to be fast.

Which approach is better? What are the differences? What is the best way to select random rows?

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