create table tbl_test (id int, info text, c_time timestamp);
insert into tbl_test select generate_series(1,100000),md5(random()::text),clock_timestamp();
select count(id) from tbl_test; --查看个数据条数

--随机字母 
select chr(int4(random()*26)+65);

--随机4位字母
select repeat( chr(int4(random()*26)+65),4);

--随机数字 十位不超过6的两位数
select (random()*(6^2))::integer;

--三位数
select (random()*(10^3))::integer;

insert into t_test SELECT generate_series(1,10000) as key,repeat( chr(int4(random()*26)+65),4), (random()*(6^2))::integer,null,(random()*(10^4))::integer;