基干表 T500是什么东西
我看《SQL COOKBOOK》时 计算两个日期之间工作日天数是用到基干表 T500。
这个基干表 到底是什么东西呢？
[解决办法]
T500 就是id从1到500 ，t500是只有id列的表
在书的前言有介绍
[解决办法]
from sql cookbook:
Additionally, you will find four pivot tables used in this book; T1, T10, T100, and T500. Because these tables exist only to facilitate pivots, I did not find it necessary to give them clever names. The number following the "T" in each of the pivot tables signifies the number of rows in each table starting from 1. For example, the values for T1 and T10:
select id from t1;
ID
----------
1
select id from t10;
ID
----------
1
2
3
4
5
6
7
8
9
10
t500存储了1-500个数字。
[解决办法]
