generate_series模拟数据环境

作者：瀚高PG实验室 （Highgo PG Lab）- 海无涯

1、普通整数数据

create table te1 (id int);


insert into te1 select generate_series(1,1000);

highgo=# select * from te1 limit 5;
 id 
----
  1
  2
  3
  4
  5
(5 rows)

2、常用规律数据模拟

create table te2  (id int,name text);


insert into te2 select generate_series(1,100),'highgo';


highgo=# select * from te2 limit 3;
 id |  name  
----+--------
  1 | highgo
  2 | highgo
  3 | highgo
(3 rows)

3、随机加密数据模拟

create table te3 (id int,MD5 vchar,TIME text);


insert into te3 select generate_series(1,5),md5(random()::highgo),clock_timestamp();


highgo=# select * from te3 limit 5;
 id |               md5                |             time              
----+----------------------------------+-------------------------------
  1 | 311e7462a6242cbc0578f9d6d91d5d33 | 2018-03-31 10:06:24.2599+08
  2 | 311e7462a6242cbc0578f9d6d91d5d33 | 2018-03-31 10:06:24.260049+08
  3 | 311e7462a6242cbc0578f9d6d91d5d33 | 2018-03-31 10:06:24.26006+08
  4 | 311e7462a6242cbc0578f9d6d91d5d33 | 2018-03-31 10:06:24.260065+08
  5 | 311e7462a6242cbc0578f9d6d91d5d33 | 2018-03-31 10:06:24.260068+08
(5 rows)

random() double 0.0到1.0之间的随机数值

highgo=# insert into te3 select generate_series(106,110),random(),clock_timestamp();
INSERT 0 5
highgo=# select * from te3 where id >105 and id < 110;
 id  |               md5                |             time              
-----+----------------------------------+-------------------------------
 106 | 0.796067376621068                | 2018-03-31 10:50:50.45065+08
 107 | 0.474363456480205                | 2018-03-31 10:50:50.450756+08
 108 | 0.771753719076514                | 2018-03-31 10:50:50.450771+08
 109 | 0.838413044810295                | 2018-03-31 10:50:50.45078+08

如需在表中添加列，请使用下列语法:

ALTER TABLE table_name  ADD column_name datatype