opc學(xué)習(xí)筆記-全文預(yù)覽
【正文】 don ( = )order by 。ANALYST39。ANA%39。計(jì)算員工的平均獎(jiǎng)金select avg(m) from emp。select job,avg(sal) from emp group by job having avg(sal) 1500 order by 2。按照職位分，查詢每類員工的平均工資select job,avg(sal) from emp group by job。計(jì)算有多少員工有經(jīng)理管理select count(mgr) from emp。NULLIF (表達(dá)式1，表達(dá)式2)select nullif(1,2) from dual。select ename,sal+nvl(m,0) ,job from emp where job not like 39。) from dual。,substr(39。L999,39。fmt39。,39。查詢結(jié)果中要求員工名稱全部首字母大寫(xiě)select initcap(ename) from emp。,39。將 I love openlab 中的 open換成oracleselect replace(39。i love openlab39。,39。 I love 39。18678788989 顯示后面4位select substr(39。) from dual。連接 I love 和 openlabselect concat(39。) from dual。I LoVe OpenLAB39。select ename,sal*12 from emp order by ename,sal*12。轉(zhuǎn)義符 escape四 排 序從小到大查詢工資大于1500的員工信息select empno,ename,sal from emp where sal =1500 order by sal。如何查詢IT_Apple的名字呢？select * from dept where dname like 39。通配符 % _select empno,ename,sal,job from emp where job like 39。PRESIDENT39。)。,39。SALESMAN39。alter session set nls_date_language = 39。查詢工資在1688和2888之間的員工信息select empno,ename,sal from emp where sal between 1688 and 2888。查詢部門(mén)編號(hào)有哪些(性能考量)呢？select deptno from emp。39。[39。查詢每個(gè)人的年薪是多少select ename||39。年薪用中文表示列頭/特殊字符用雙引號(hào)select ename as 名稱,(sal+500)*12 年薪 from emp。scott維護(hù)alter user scott identified by tiger account unlock。 代表一個(gè)字符escape 轉(zhuǎn)移符 like 39。有條件 〉〈 ！= 〈〉between and in (A,B,C)like 39。OPC學(xué)習(xí)筆記一db基礎(chǔ)知識(shí)Linix環(huán)境下$. oraenv/sid（數(shù)據(jù)庫(kù)名字） sid=orcl/home(數(shù)據(jù)庫(kù)路徑） home=/u01/..../dbsqlplus sys/ ****(任 意) as sysdba(都可以聯(lián)上）[sysdba用戶]connect idle instance(連接到了一個(gè)空閑的實(shí)例上，服務(wù)沒(méi)有開(kāi)）需要startup啟動(dòng)默認(rèn)實(shí)例Windows環(huán)境下sql /nolog (不登陸，只連接到軟件）conn / as sysdba（以AS用戶連接到數(shù)據(jù)庫(kù)）sqlplus sys/ ****(任 意) as sysdba(都可以聯(lián)上）show user(顯示用戶）sqlplus scott/tiger默認(rèn)用戶：scott 默認(rèn)密碼：tigeralter user scott account lock:(用戶名鎖定）alter user scott identified by tiger account unlock:(將用戶scott的密碼改成tiger并解鎖)select * from cat。+ * / （ ）別名 連接符 ||edit （編輯）編輯器中注不要加‘；’list (顯示上一次成功運(yùn)行的命令）alter session set NLS_DATE_LANGUAGE=americandistinct(去重復(fù)）找重復(fù)的記錄insert into 表名val ()mit。_39。~39。查詢加工資后每個(gè)員工的年薪select ename,sa
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