为什么不要使用 select * from xxx (oracle 亲测)

Posted 2020-12-03 bailaowu

打开已用时间
set timing on;
create table users(id number(20), name varchar2(20), password varchar2(20));
insert into users values(111111111111111, ‘爱新觉罗·启星‘, ‘[email protected]‘);
insert into users(id, name, password) select * from users; // 插入32768条数据
select * from users; 用时40.58秒
select name from users; 用时23.34秒
select * from users; 用时38.58秒
select name from users; 用时23.91秒
select * from users; 用时39.47秒
select name from users; 用时24.28秒