https://blog.youkuaiyun.com/alee007zh-cnhttps://blog.youkuaiyun.com/https://blog.youkuaiyun.com/alee007/article/details/5639131https://blog.youkuaiyun.com/alee007/article/details/5639131alee007Tue, 01 Jun 2010 13:01:00 +0800在上一篇中，我们讲到了多线程是如何处理共享资源的，以及保证他们对资源进行互斥访问所依赖的重要机制：对象锁。

本篇中，我们来看一看传统的同步实现方式以及这背后的原理。

很多人都知道，在Java多线程编程中，有一个重要的关键字，synchronized。但是很多人看到这个东西会感到困惑：“都说同步机制是通过对象锁来实现的，但是这么一个关键字，我也看不出来Java程序锁住了哪个对象阿？“

没错，我一开始也是对这个问题感到困惑和不解。不过]]>https://blog.youkuaiyun.com/alee007/article/details/5639128https://blog.youkuaiyun.com/alee007/article/details/5639128alee007Tue, 01 Jun 2010 12:59:00 +0800众所周知，在Java多线程编程中，一个非常重要的方面就是线程的同步问题。
关于线程的同步，一般有以下解决方法：

1. 在需要同步的方法的方法签名中加入synchronized关键字。
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2. 使用synchronized块对需要进行同步的代码段进行同步。
转载注明出处：http://]]>https://blog.youkuaiyun.com/alee007/article/details/5639115https://blog.youkuaiyun.com/alee007/article/details/5639115alee007Tue, 01 Jun 2010 12:55:00 +0800问题：

语句1 ：
Select * from  table1 A where A.col1 not in ( select col1 from table2 B )

转载注明出处：http://x- spirit.javaeye.com/、http: //www.blogjava.net/zhangwei217245/
如果这样，本来应该有一条数据，结果没有。
如果我改写成这样：

语句2 ：<]]>https://blog.youkuaiyun.com/alee007/article/details/3947856https://blog.youkuaiyun.com/alee007/article/details/3947856alee007Sun, 01 Mar 2009 21:25:00 +0800https://blog.youkuaiyun.com/alee007/article/details/2227164https://blog.youkuaiyun.com/alee007/article/details/2227164alee007Sat, 29 Mar 2008 01:19:00 +0800https://blog.youkuaiyun.com/alee007/article/details/604765https://blog.youkuaiyun.com/alee007/article/details/604765alee007Tue, 21 Feb 2006 19:25:00 +0800https://blog.youkuaiyun.com/alee007/article/details/476974https://blog.youkuaiyun.com/alee007/article/details/476974alee007Sat, 10 Sep 2005 14:18:00 +0800https://blog.youkuaiyun.com/alee007/article/details/476969https://blog.youkuaiyun.com/alee007/article/details/476969alee007Sat, 10 Sep 2005 14:15:00 +0800https://blog.youkuaiyun.com/alee007/article/details/472378https://blog.youkuaiyun.com/alee007/article/details/472378alee007Tue, 06 Sep 2005 09:29:00 +0800https://blog.youkuaiyun.com/alee007/article/details/467914https://blog.youkuaiyun.com/alee007/article/details/467914alee007Tue, 30 Aug 2005 14:59:00 +0800https://blog.youkuaiyun.com/alee007/article/details/458970https://blog.youkuaiyun.com/alee007/article/details/458970alee007Fri, 19 Aug 2005 16:25:00 +0800https://blog.youkuaiyun.com/alee007/article/details/344817https://blog.youkuaiyun.com/alee007/article/details/344817alee007Tue, 12 Apr 2005 18:53:00 +0800https://blog.youkuaiyun.com/alee007/article/details/344735https://blog.youkuaiyun.com/alee007/article/details/344735alee007Tue, 12 Apr 2005 17:52:00 +0800A.成绩),0)+1 as 名次,* from t Aorder by 成绩 desc1、Select *,IsNull((Select sum(1) from t1 where 总分>a.总分),0)+1 as 名次 from t1 aorder by (Select sum(1) from t1 wh]]>https://blog.youkuaiyun.com/alee007/article/details/257590https://blog.youkuaiyun.com/alee007/article/details/257590alee007Tue, 18 Jan 2005 10:36:00 +0800https://blog.youkuaiyun.com/alee007/article/details/200252https://blog.youkuaiyun.com/alee007/article/details/200252alee007Wed, 01 Dec 2004 10:56:00 +0800https://blog.youkuaiyun.com/alee007/article/details/199561https://blog.youkuaiyun.com/alee007/article/details/199561alee007Tue, 30 Nov 2004 18:52:00 +0800https://blog.youkuaiyun.com/alee007/article/details/199558https://blog.youkuaiyun.com/alee007/article/details/199558alee007Tue, 30 Nov 2004 18:47:00 +0800https://blog.youkuaiyun.com/alee007/article/details/199557https://blog.youkuaiyun.com/alee007/article/details/199557alee007Tue, 30 Nov 2004 18:45:00 +0800https://blog.youkuaiyun.com/alee007/article/details/168369https://blog.youkuaiyun.com/alee007/article/details/168369alee007Fri, 05 Nov 2004 11:36:00 +0800https://blog.youkuaiyun.com/alee007/article/details/143765https://blog.youkuaiyun.com/alee007/article/details/143765alee007Wed, 20 Oct 2004 09:56:00 +0800