大约有 40,000 项符合查询结果（耗时：0.0309秒） [XML]
一个故事告诉你比特币的原理及运作机制 - 创意 - 清泛网 - 专注C/C++及内核技术
...这样以物易物实在太不方便了，于是村子全员开会，讨论如何解决这个问题。有人提议，以便于分割且稀有的东西，例如黄金，作为一般等价物，把其它物品和黄金的对应关系编成一张表格，例如一克黄金对应一只羊，一克黄金...
MySQL - Rows to Columns
...ts, but I only found solutions for SQL Server/Access. I need a solution in MySQL (5.X).
12 Answers
...
Quick and easy file dialog in Python?
... show only the dialog without any other GUI elements, you have to hide the root window using the withdraw method:
import tkinter as tk
from tkinter import filedialog
root = tk.Tk()
root.withdraw()
file_path = filedialog.askopenfilename()
Python 2 variant:
import Tkinter, tkFileDialog
root = T...
Using DISTINCT and COUNT together in a MySQL Query
Is something like this possible:
7 Answers
7
...
Resolving javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path
...TPS SSL certificate, and our older version of java doesn’t recognize the root certificate authority (CA).
• If you can access the HTTPS URL in your browser then it is possible to update Java to recognize the root CA.
• In your browser, go to the HTTPS URL that Java could not access. Click on t...
SQL statement to get column type
...
If you're using MySQL you could try
SHOW COLUMNS FROM `tbl_name`;
SHOW COLUMNS on dev.mysql.com
Otherwise you should be able to do
DESCRIBE `tbl_name`;
share
...
mysql实现split分割字符串（length, SUBSTRING_INDEX, substring） - 爬虫/...
由于MySql没有直接的split函数，只提供了length, SUBSTRING_INDEX, substring三个函数，这里介绍如何用这三个函数实现split功能。
# SUBSTRING_INDEX(str, delim, count)：返回字符串 str 中在第 count 个出现的分隔符 delim 之前的子串。如果 count 是...
Mysql substr和Oracle substr区别 - 爬虫/数据库 - 清泛IT社区，为创新赋能！
Oracle substr(字符串，开始索引、从0起，长度)
Mysql substr或substring(字符串，开始索引、从1起，长度)
新手程序员应该知道的7件事 - 创意 - 清泛网 - 专注C/C++及内核技术
...。掌握类似于find、comm、diff、vi/vim、sed、awk等工具。知道如何用命令行来查找文件等等，都可以在你写脚本的时候为你减负。”
Bull，是一位先用微软工具，然后逐渐转移到Linux的程序员，对此表示赞同：“了解命令行的来龙去...
MySQL Multiple Joins in one query?
....new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f8974328%2fmysql-multiple-joins-in-one-query%23new-answer', 'question_page');
}
);
Post as a guest
...