原文:05. 取SQL分组中的某几行数据对表中数据分组,有时只需要某列的聚合值;有时却需要返回整行数据,常用的方法有:子查询、ROW_NUMBER、APPLY,总体感觉还是ROW_NUMBER比较直观。测试数据: if OBJECT_ID('testGroup') is not null
drop ...
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数据库 时间:
2014-09-06 12:10:43
阅读次数:
353
传送门Seek the Name, Seek the FameTime Limit: 2000MSMemory Limit: 65536KDescriptionThe little cat is so famous, that many couples tramp over hill and dal...
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其他好文 时间:
2014-09-04 22:03:40
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240
Https协议:SSL建立过程分析web訪问的两种方式:http协议,我们普通情况下是通过它訪问web,由于它不要求太多的安全机制,使用起来也简单,非常多web网站也仅仅支持这样的方式下的訪问.https协议(Hypertext Transfer Protocol over Secure Socke...
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其他好文 时间:
2014-09-04 20:51:30
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284
select?*?from?(select?row_number()over(order?by?Server_no?desc)?as?rownum,Server_no,Game_Name,Server_name?from?T_GameServer_List?where?IS_DELETE?=?‘N‘?and?Game_name?like?‘%q%‘)a...
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数据库 时间:
2014-09-03 21:23:27
阅读次数:
215
Little Tim is now a graduate,and is thinking about higher studies. However, he first needs to appear in anexam whose preparation alone includes memorizing the meanings of over 3500words!
After going ...
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其他好文 时间:
2014-09-03 13:10:06
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241
Mobile is no longer on the sidelines. If you’re not already thinking mobile first, you should at least consider it. Let’s go over compelling data that...
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Web程序 时间:
2014-09-03 10:50:56
阅读次数:
235
Attack on Titans
Time Limit: 2 Seconds Memory Limit: 65536 KB
Over centuries ago, mankind faced a new enemy, the Titans. The difference of power between mankind and their newfound enemy was...
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其他好文 时间:
2014-09-03 09:44:47
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297
The JSR-133 Cookbook for Compiler Writers
by Doug Lea,
with help from members of the JMM mailing list.
dl@cs.oswego.edu.
Preface: Over the 10+ years since this was initially written, many process...
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Web程序 时间:
2014-09-03 09:40:06
阅读次数:
432
代码思路如下:select *,(@row_num:=@row_num+1) as row_no from stc_output,(select(@row_num:=0)) b;select * from (select *,(@row_num:=@row_num+1) as row_no from...
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数据库 时间:
2014-09-02 19:33:35
阅读次数:
253
实际测试:数据库:70万条数据查询第10000页,每页10条。row_number() 耗时: 2.2秒rownum 耗时:1.3秒查询第20000页,每页10条。row_number() 耗时: 4.5秒+rownum 耗时:3.8秒+ 网上看到的说,row_number()效率最高看来是没有经....
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其他好文 时间:
2014-09-02 13:58:14
阅读次数:
216