为什么.NET中没有通用的同步队列?(Why is there no generic synchronized queue in .NET?)
我注意到你可以调用Queue.Synchronize来获得一个线程安全的队列对象,但是同样的方法在Queue <T>上不可用。 有谁知道为什么? 似乎有点奇怪。
I noticed that you can call Queue.Synchronize to get a thread-safe queue object, but the same method isn't available on Queue<T>. Does anyone know why? Seems kind of weird.
原文:https://stackoverflow.com/questions/107117
更新时间:2024-02-21 21:02
最满意答案
create table a (id number(10), name varchar2(10), score number(10)); insert into a values (1,'a',111); insert into a values (2,'b',222); insert into a values (3,'c',78); insert into a values (4,'d',11); insert into a values (5,'v',111); commit; select a.*, b.* from (select a.*, row_number() over(order by a.id) rn from a where mod(a.id, 2) = 1) a, (select a.*, row_number() over(order by a.id) rn from a where mod(a.id, 2) = 0) b where a.rn=b.rn(+);
其他回答
(1) select deptno from dept where depptno in (select deptno from em); (2)select empno,ename,sal from em where sal>(select sal from em where ename = 'smith'); (3)select e.ename,d.dname from em e,dept d where e.deptno=d.deptno and e.job = 'clerk'; (4)select empno,ename from em where job in (select job from em where ename = 'scott') ; (5)select job,min(sal) from em group by job; (6)select d.dname ,min(e.sal) from dept d,em e where d.deptno=e.deptno and e.job ='manager' group by d.dname;
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