import java.util.concurrent.CountDownLatch; public class TestThread { static int cnt = 100; static int last = -1; static int type = 2; static int liveCnt = cnt; static CountDownLatch counter = new CountDownLatch(cnt); static class WorkThread extends Thread { Object lock = null; int id = -1; int sleep = -1; WorkThread(int id, Object lock)...
by thrack - Java文档中心 - 2008-12-12 11:45:52 阅读(1272) 回复(0)
想用wait()来获得任一子进程的结束 #include "sys/types.h" #include "sys/wait.h" #include "stdio.h" main() { pid_t pid; if((pid=fork())<0) {printf("fork error."); exit(0); } else if (pid==0) { printf("1 ID:%d\n",getpid()); if ((pid=fork())<0) {printf("fork error."); exit(0); } else if (pid==0) { printf("2 ID:%d\n",getpid()); exit(0); } else sleep(2); } else printf("...
表A记录如下:aID aNum1 a200501112 a200501123 a200501134 a200501145 a20050115表B记录如下:bID bName1 20060324012 20060324023 20060324034 20060324048 2006032408 创建这两个表SQL语句如下:CREATE TABLE a aID int( 1 ) AUTO_INCREMENT PRIMARY KEY , aNum char( 20 ) ) CREATE TABLE b( bID int(...
MySQL支持下列用于SELECT语句的join句法: table_reference, table_reference table_reference [CROSS] join table_reference table_reference INNER join table_reference table_reference STRAIGHT_join table_reference table_reference LEFT [OUTER] join table_reference ON conditional_expr table_reference LEFT [OUTER] join table_reference USING (column_list) table_reference NATURAL LEFT [OUTER] join table_ref...
定义和用法 在join( )函数返回一个字符串的内容阵列。 在join( )函数是一个别名的inplode( )函数。 语法 join(separator,array)ParameterDescriptionseparator任择。指定放什么东西到之间的数组元素。默认为“ ” (空字符串)array必需的。阵列join到一个字符串 提示和说明 注:join( )函数接受其参数要么秩序。然而,对于符合爆炸( ) ,你应该使用记录命令的论点。 注:分隔参数的join( )是可选的。但是,建议总...
我不会join query, 试了很多次都失败了。:em16: :em16: 请高手给些例子吧。突然觉得还是sql语言很方便。 下面有连个data files. db1 和db2 --------------------- db1有以下栏位 A1, B1, C1 ---------------------- db2有以下栏位 A2, B2, C2 ---------------------- sql语句是: select *all from db1 and db2 where A1=A2 and B1=6 and C2>5 哪位高手可以 把sql语句 翻译成 opnqryf 语句?? :sh...
join 分为内连接,外连接(左外连接,右外连接,全外连接) 内连接: SELECT A.* FROM A INNER join B ON A.ID=B.ID 左外连接: SELECT A.* FROM A LEFT join B ON A.ID = B.ID 右外连接: SELECT A.* FROM A RIGHT join B ON A.ID = B.ID 全外连接: SELECT A.*, B.* FROM A FULL OUTER join B ON A.ID = B.ID inner join 就是所有记录都要有,左边的表和右边的表都要有记录。 left join 就是只要满足左边的表的条件就行...
本文转自: http://www.wellho.net/archives/2004/12/index.html#000158 MySQL - LEFT join and RIGHT join, INNER join and OUTER join In a database such as MySQL, data is divided into a series of tables (the "why" is beyond what I'm writing today) which are then connected together in SELECT commands to generate the output required. I find when I'm running MySQL training , people often get confused b...