Postgresql. Generate sets of random integers

Question

With this command I can generate 16384 random integers between 1 AND 200,000.

SELECT generate_series (1,16384),(random()*200000)::int AS id

I want to generate 10 sets of such integers. Each set must have an integer identifier, something like that:

1 | 135

1 | 1023

... end of first set of 16384 random numbers

2 | 15672

2 | 258732

... end of second set of 16384 random numbers

Is this possible with an SQL command, or should I write a function for that?

Answer 1

Would this be what you want?

SELECT 
 n, generate_series (1,16384), (random()*200000)::int AS id 
FROM 
 generate_series (1,10) AS x(n) ;

or the similar:

SELECT 
 n, i, (random()*200000)::int AS id 
FROM 
 generate_series (1,10) AS x(n) 
 CROSS JOIN
 generate_series (1,16384) AS y(i) ;

Answer 2

You can do something like this:

SELECT ((generate_series-1)/16384)::int+1 as series, (random()*200000)::int as rand
 from generate_series(1,10*16384);

This does the sampling with replacement. If it needs to be done without replacement, that is quite a bit hard.