昨天拙文中讲述了用自增方式创建一千六百万大表的方案,这回讨论的是用笛卡儿积,实践证明这种方案更快. 2020年3月15日08点58分实验开始 创建仅有四千数据的tb_4thousand1表: SQL> CREATE TABLE tb_4thousand1 2 ( 3 id NUMBER not null primary key, 4 name NVARCHAR2(60) not null, 5 salary int NOT NULL, 6 createtime TIMESTAMP (6) not
declare @starttime as datetime declare @endtime as datetime set @starttime = '2009-11-24 15:10:00' set @endtime = '2009-11-24 15:12:24' )+':'+ )+':'+ ) as TimeEd 定义为函数 create FUNCTION [f_TimeBetween] ( @start datetime, @end datetime ) ) AS BEGIN )+':