最新回答 / weixin_慕工程1563154
https://vk.com/album712774205_283337118https://vk.com/album712534118_283387603https://vk.com/album712782889_283685620https://vk.com/album712781708_283387621https://vk.com/album712782082_283433465https://vk.com/album712782483_285962937https://vk.com/album7...
2019-08-02
最新回答 / 慕沐6523080
select ci_id,MAX(M) from (select ci_id,wm_concat(stu_name) over (partition by c.ci_id order by s.stu_id)m from pm_ci c,pm_stu s where instr(c.stu_ids,s.stu_id)>0)e group by e.ci_id;
2019-06-27
已采納回答 / Johnny_t
select 1 from dual where null != null;select 1 from dual where null is null;
2019-04-25
已采納回答 / Amousy
<...code...>用distinct可以找到不重復記錄，
select?distinct?mgr?from?emp?where?mgr?is?not?null;上面這條語句的功能可以找到所有老板。很明顯King（7839）是包括在里面的，為什么select * from e...
2019-03-24
最贊回答 / 大王叫我來巡山570127
1、先創建表及初始化數據?①創建及初始化學生表PM_STUcreate table PM_STU(STU_ID? ? ? ? ? ?VARCHAR2(20) NOT NULL,? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? STU_NAME? ? ? VARCHAR2(20));? ? ? ? ? ? ? ??INSERT INTO? PM_STU VALUES(1,'張三');INSERT INTO? PM_STU VALUES(2,'李四');INSERT INTO? PM_STU...
2019-01-06