大约有 11,400 项符合查询结果（耗时：0.0173秒） [XML]
SQL to find the number of distinct values in a column
...gregate function:
SELECT COUNT(DISTINCT column_name) AS some_alias FROM table_name
This will count only the distinct values for that column.
share
|
improve this answer
|
...
Best way to assert for numpy.array equality?
...__eq__ returns a new array (so TestCase.assertEqual fails), what is the best way to assert for equality?
6 Answers
...
数据结构、算法复杂度一览表 - 更多技术 - 清泛网移动版 - 专注C/C++及内核技术
...omplexities常用算法、数据结构复杂度一览表。来源：http://bigocheatsheet.com/
搜索算法(来源)
算法
数据结构
时间复杂度
空间复杂度
平均
最差
最差
深度优先搜索
图G(V,E), V为顶...
Best/Most Comprehensive API for Stocks/Financial Data [closed]
What is the most recommended free/public API for accessing financial market stats and stock quotes (preferrably real-time quotes)? I'm not too picky about how it's exposed (SOAP, REST, some proprietary XML setup, etc.), as long as it's got some decent documentation.
...
Benchmarking (python vs. c++ using BLAS) and (numpy)
I would like to write a program that makes extensive use of BLAS and LAPACK linear algebra functionalities. Since performance is an issue I did some benchmarking and would like know, if the approach I took is legitimate.
...
Questions every good .NET developer should be able to answer? [closed]
My company is about to hire .NET developers . We work on a variety of .NET platforms: ASP.NET, Compact Framework, Windowsforms, Web Services. I'd like to compile a list/catalog of good questions, a kind of minimum standard to see if the applicants are experienced. So, my question is:
...
sqlite3-ruby install error on Ubuntu
I have the following error during sqlite3-ruby install:
19 Answers
19
...
What are the best practices for SQLite on Android?
What would be considered the best practices when executing queries on an SQLite database within an Android app?
10 Answers
...
Extracting hours from a DateTime (SQL Server 2005)
I can extract the month and day by using Day(Date()) , Month(Date()) . I can't extract hours, with HOUR(Date()) . I get the following error.
...
Convert a negative number to a positive one in JavaScript
Is there a math function in JavaScript that converts numbers to positive value?
16 Answers
...