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Unicode与UTF-8互转(C语言实现) - C/C++ - 清泛网 - 专注C/C++及内核技术
...了符号的二进制代码, 却没有规定这
个二进制代码应该如何存储".
比如, 汉字"严"的unicode是十六进制数4E25, 转换成二进制数足足有15位
(100111000100101), 也就是说这个符号的表示至少需要2个字节. 表示其他更大的符号,
可能需要3...
Getting the minimum of two values in SQL
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For MySQL or PostgreSQL 9.3+, a better way is to use the LEAST and GREATEST functions.
SELECT GREATEST(A.date0, B.date0) AS date0,
LEAST(A.date1, B.date1, B.date2) AS date1
FROM A, B
WHERE B.x = A.x
With:
GREATEST(v...
大数据：用数据指导APP运营 - 资讯 - 清泛网 - 专注C/C++及内核技术
...感觉在不知不觉中获得了提升，这一点，非常重要。
3 如何获取数据
获取数据的渠道有很多，而方式基本就是自己做和使用外部工具两种方式。
自己做的话，App可以选择“埋点”、log等方式，而Web可以通过log、日志与按钮埋...
Possible to perform cross-database queries with PostgreSQL?
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If you're coming from a MySQL environment, what MySQL calls databases are really schemas (CREATE SCHEMA == CREATE DATABASE in MySQL), so if you porting something from MySQL using multiple databases, use schemas
– MkV
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Overriding id on create in ActiveRecord
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Perhaps what I experienced only expressed itself with mysql driver.
– jkndrkn
Feb 18 '13 at 19:30
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SQL select only rows with max value on a column [duplicate]
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I know that MySQL allows you to add non aggregate fields to a "grouped by" query, but I find that kinda pointless. Try running this select id, max(rev), rev from YourTable group by id and you see what I mean. Take your time and try to un...
Windows下 C++网络延时检测 - C/C++ - 清泛网 - 专注C/C++及内核技术
...低延时、负载较低的服务器节点。例如：那么这个功能是如何实现的呢？...一般需要连接服务器后端的软件都有服务器节点网络延迟的检测，帮助选择低延时、负载较低的服务器节点。例如：
那么这个功能是如何实现的呢？...
中关村服务辐射百万创业者 - 资讯 - 清泛网 - 专注C/C++及内核技术
...间、人才、资本……成为拦在创业道路上的种种难题。
如何才能在日益变化的环境下更好地帮到创业者，成为摆在创业服务业面前的最大问题。6月25日，清控科创携手清华控股、北极光创投、完美时空、银杏天使、创业邦、盛...
How to test an SQL Update statement before running it?
...What about Transactions? They have the ROLLBACK-Feature.
@see https://dev.mysql.com/doc/refman/5.0/en/commit.html
For example:
START TRANSACTION;
SELECT * FROM nicetable WHERE somthing=1;
UPDATE nicetable SET nicefield='VALUE' WHERE somthing=1;
SELECT * FROM nicetable WHERE somthing=1; #check
CO...
How do I select an entire row which has the largest ID in the table?
...show profiles and it appears our solutions have the same performance using MySQL. For my own knowledge, do you know what DBMS has poorer performance for subselects?
– unutbu
Feb 7 '14 at 20:08
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