【正文】 D.SELECT DISTINCT(cid) FROM orders o1,orders o2 WHERE =’p01’ AND =’p02’正確答案：C 47.(多選)下列語句在建表的同時在c2,c3列上創(chuàng)建了唯一約束，其中正確的是：o A.create table test (c1 number constraint test_c1_pk primary key, c2 number constraint test_c2_uk foreign key, c3 number constraint test_c3_uk foreign key)。o B.create table test (c1 number constraint test_c1_pk primary key, c2 number , c3 number , constraint test_c3_uk foreign key(c2,c3))。o C.create table test (c1 number constraint test_c1_pk primary key, c2 number , c3 number , constraint test_c3_uk unique(c2,c3))。o D.create table test (c1 number constraint test_c1_pk primary key, c2 number constraint test_c2_uk unique, c3 number constraint test_c3_uk unique)。正確答案：CD 48.(多選)請看下列建表語句： create table test( c1 number(3) constraint test_c1_pk primary key, c2 number(2) , c3 number(2) , constraint test_c2_ck check (( c2 + c3 ) 100) )。 下列選項中能向test表中成功實施插入數(shù)據(jù)的插入語句是：o A.insert into test values (1,40,60)。o B.insert into test values (2,41,61)。o C.insert into test values (3,101,1)。o D.insert into test values (4,50,51)。正確答案：BD 49.(多選)操作account表和service表，查詢申請遠程登錄業(yè)務(wù)的客戶的數(shù)據(jù)，下列sql語句正確的是：o A.select real_name from account where in (select account_id from service)。o B.select real_name from account o where id exists (select 1 from service i where = )。o C.select real_name from account where id in (select account_id from service)。o D.select real_name from account o where exists (select 1 from service i where = )。正確答案：CD 50.(多選題)操作account表和age_segment表，查詢客戶huangrong的年齡段，下列sql語句正確的是：o A.select real_name,birthdate, from account a join age_segment s on round((sysdate birthdate)/365) between lowage and hiage and real_name = 39。huangrong39。o B.select real_name,birthdate, from account a left join age_segment s on round((sysdate birthdate)/365) between lowage and hiage and real_name = 39。huangrong39。o C.select real_name,birthdate, from account a left join age_segment s on round((sysdate birthdate)/365) between lowage and hiage where real_name = 39。huangrong39。o D.select real_name,birthdate, from account a left join age_segment s on round((sysdate birthdate)/365) between lowage and hiage。正確答案：ACon和where的區(qū)別在于 on條件是在生成臨時表時使用的條件 它不管on中的條件是否為真 都會返回左邊表中的記錄 where條件是在臨時表生成之后 再對臨時表進行過濾 這時已經(jīng)沒有l(wèi)eft join的含義（必須返回左邊表的記錄）了 條件不為真的就全部過濾掉 所以B選項和C選項的寫法其實換一種方式就比較明顯了 B. select real_name,birthdate, from account a left join age_segment s on (round((sysdate birthdate)/365) between lowage and hiage and real_name = 39。huangrong39。)。 C. select real_name,birthdate, from account a left join age_segment s on (round((sysdate birthdate)/365) between lowage and hiage) where real_name = 39。huangrong39。 B選項on的條件是 round((sysdate birthdate)/365) between lowage and hiage and real_name = 39。huangrong39。 C選項on的條件是 round((sysdate birthdate)/365) between lowage and hiage關(guān)于我們|服務(wù)支持|咨詢與反饋|最新動態(tài)|代理合作|名師堂達內(nèi)時代科技集團有限公司 20132014中關(guān)村中心企業(yè)合作：62117598 UID中心企業(yè)合作：821684282168831歡迎您的光臨，！希望您提出您寶貴的意見，你的意見是我進步的動力。贈語； 如果我們做與不做都會有人笑，如果做不好與做得好還會有人笑，那么我們索性就做得更好，來給人笑吧！ 現(xiàn)在你不玩命的學(xué)，以后命玩你。我不知道年少輕狂，我只知道勝者為王。不要做金錢、權(quán)利的奴隸；應(yīng)學(xué)會做“金錢、權(quán)利”的主人。什么時候離光明最近？那就是你覺得黑暗太黑的時候。最值得欣賞的風(fēng)景，是自己奮斗的足跡。壓力不是有人比你努力，而是那些比你牛幾倍的人依然比你努力。 參考