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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 CONCAT returns NULL if any field contain NULL
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mysql has IFNULL(arg, default) instead COALESCE with the same syntax
– Vasilii Suricov
Feb 19 '19 at 17:58
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Count table rows
What is the MySQL command to retrieve the count of records in a table?
11 Answers
11
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Get current AUTO_INCREMENT value for any table
How do I get the current AUTO_INCREMENT value for a table in MySQL?
8 Answers
8
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MySQL Removing Some Foreign keys
I have a table whose primary key is used in several other tables and has several foreign keys to other tables.
11 Answers
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Difference between BeautifulSoup and Scrapy crawler?
...ter extraction. For example we can configure pipeline to push data to your mysql server.
Cookies: scrapy automatically handles cookies for us.
etc.
TLDR: scrapy is a framework that provides everything that one might
need to build large scale crawls. It provides various features that
hide c...
Common MySQL fields and their appropriate data types
I am setting up a very small MySQL database that stores, first name, last name, email and phone number and am struggling to find the 'perfect' datatype for each field. I know there is no such thing as a perfect answer, but there must be some sort of common convention for commonly used fields such as...
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...
SQLite INSERT - ON DUPLICATE KEY UPDATE (UPSERT)
MySQL has something like this:
5 Answers
5
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MySQL COUNT DISTINCT
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