drop table if exists tab1;
create table tab1 (
	id serial primary key
	, ival integer
	, tval text
	, tsval timestamp(0) default now()
);

insert into tab1 (ival, tval)
SELECT x, chr(x) FROM (
	SELECT generate_series(1,50), ascii('A') + width_bucket(random(), 0, 1, ascii('z') - ascii('A')) as x
)src
;


select * from tab1;