一.sql語句1.增加主鍵 alter table TABLE_NAME add constraint KEY_NAME primary key (TABLE_COLUMN); 指定表空間 alter table TABLE_NAME add constraint KEY_NAME primary key (TABLE_COLUMN) using index; tablespace TABLE_SPACE_NAME;2.增加外鍵 alter table TABLE_NAME add constraint FK_NAME; foreign key (TABLE_COLUMN) references KEY_TABLE_NAME;3.使主鍵或外鍵失效、生效 alter table TABLE_NAME; disable(enable) constraint KEY_NAME;4、查看各種約束 select constraint_name,table_name,constraint_type,status from user_constraints; select constraint_name, constraint_type,search_condition, r_constraint_name; from user_constraints where table_name = upper('&table_name'); select c.constraint_name,c.constraint_type,cc.column_name; from user_constraints c,user_cons_columns cc where c.owner = upper('&table_owner') and c.table_name = upper('&table_name') and c.owner = cc.owner and c.constraint_name = cc.constraint_name order by cc.position; 5、刪除主鍵或外鍵 alter table TABLE_NAME; drop constraint KEY_NAME;6、建外鍵 單字段時：create table 表名 (col1; char(8), cnochar(4); REFERENCE course); 多個字段時,在最后加上 Foreign Key (字段名) REFERENCE 表名(字段) 連帶刪除選項 (on delete cascade 當指定時，假如父表中的記錄被刪除，則依靠于父表的記錄也被刪除 REFERENCE 表名（） on delete cascade;7、刪除帶約束的表 Drop table 表名 cascade; constraints;8：索引治理<1>.creating function-based indexes sql> create index summit.item_quantity on summit.item(quantity-quantity_shipped); <2>.create a B-tree index sql> create [unique] index index_name on table_name(column,.. asc/desc) tablespace sql> tablespace_name [pctfree integer] [initrans integer] [maxtrans integer] sql> [logging nologging] [nosort] storage(initial 200k next 200k pctincrease 0 sql> maxextents 50); <3>.pctfree(index)=(maximum number of rows-initial number of rows)*100/maximum number of rows <4>.creating reverse key indexes sql> create unique index xay_id on xay(a) reverse pctfree 30 storage(initial 200k sql> next 200k pctincrease 0 maxextents 50) tablespace indx; <5>.create bitmap index sql> create bitmap index xay_id on xay(a) pctfree 30 storage( initial 200k next 200k sql> pctincrease 0 maxextents 50) tablespace indx; <6>.change storage parameter of index sql> alter index xay_id storage (next 400k maxextents 100); 7.allocating index space sql> alter index xay_id allocate extent(size 200k datafile 'c:/Oracle/index.dbf'); <8>.alter index xay_id deallocate unused; <9>、查看索引 ;SQL>select index_name,index_type,table_name from user_indexes order by table_name;<10>、查看索引被索引的字段 ;SQL>select * from user_ind_columns where index_name=upper('&index_name');11、創建序列 select * from user_sequences; create; sequence SEQ_NAME; start with 1000 maxvalue; 1000 increment by 1; alter sequence; SEQ_NAME minvalue 50 maxvalue 100;12、刪除重復行 update a set aa=null where aa is not null; delete from a where rowid!= (select max(rowid) from a; b where; a.aa=b.aa);13、刪除同其他表相同的行 delete from a; where exits (select 'X' from b where b.no=a.no); 或 delete from a; where no in (select no from b);14、查詢從多少行到多少行的記錄(可以用在web開發中的分頁顯示);select * from ( select rownum row_id,b.* from (select a.* from sys_oper a) b )where row_id between 15 and 2015、對公共授予訪問權 grant select on 表名 to public; create public synonym 同義詞名; for 表名;16、填加注釋 comment on table 表名 is; '注釋'; comment on column 表名.列名 is '注釋';17、分布式數據庫,創建數據庫鏈路 create [public] database link LINKNAME [connect to USERNAME identified by PASSWord] [using 'CONNECT_STRING'] 可以在服務器端，也可以在客戶端建立，但必須注重，兩臺服務器之間 數據庫必須可以互訪，必須各有各自的別名數據庫18、查看數據庫鏈路 select * from; all_db_links; select * from user_db_links; 查詢; select * from TABLENAME@DBLNKNAME 創建遠程數據庫同義詞 create synonym; for TABLENAME@DBLNKNAME 操縱遠程數據庫記錄 insert into TABLENAME@DBLNKNAME (a,b); values (va,vb); update;TABLENAME@DBLNKNAME set a='this'; delete from TABLENAME@DBLNKNAME 怎樣執行遠程的內嵌過程 begin otherdbpro@to_html(參數); end;19、數據庫鏈路用戶密碼有非凡字符的時候，可以用雙引號把密碼引起來create public database link dblink1 connect to db1 identified by '123*456' using 'db11'20.oracle8中擴充了group by rollup和cube的操作。有時候省了你好多功夫的。<1>下面的語句可以進行總計select region_code,count(*) from aicbs.acc_woff_notifygroup by rollup(region_code);<2> 對第1個字段小計，最后合計select region_code,write_status,count(*) from aicbs.acc_woff_notifygroup by rollup(region_code,write_status);----------------------570;;0;;;;3570;;1;;;;2570;;5--此處小計了570的記錄571;;0;;;;10571;;1;;;;2571;;12; --此處小計了571的記錄.....100 --此處有總計<3> 復合rollup表達式,只做總計select region_code,write_status,count(*) from aicbs.acc_woff_notifygroup by rollup(region_code,write_status);<4> 對第1個字段小計，再對第2個字段小計，最后合計select region_code,write_status,count(*) from aicbs.acc_woff_notifygroup by cube(region_code,write_status);----------------------100 ;--此處有總計0;;60;;--對write_status＝0的小計1;;39;;--對write_status＝1的小計3;;1;;--對write_status＝3的小計570;;;;5;;--此處小計了570的記錄570;;0;;3570;;1;;2571;;;;12;;--此處小計了571的記錄571;;0;;10571;;1;;2....<3> 復合cube表達式,只做總計select region_code,write_status,count(*) from aicbs.acc_woff_notifygroup by cube(region_code,write_status);<4>下面的語句可以按照rollup不同的字段進行小計select region_code,write_status,count(*) from aicbs.acc_woff_notifygroup by region_code,rollup(write_status);21.查詢view的創建語句 sql>set long 1000 sql>select * from user_views where view_name='MY_VIEW_NAME'; orsql>select * from all_views where view_name='MY_VIEW_NAME';22、去除數據庫中非凡字符 ;<1>.字符串字段中含有''',假如用來組合sql語句，會造成語句不準確。 比如：replace(f1,'''','')<2>.字符串字段中含有't n',假如用來在c或者c＋＋程序中輸出到文件，格式無法保證。比如：replace(f2,'t','')<3>.清除換行和回車比如: replace(f2,chr(13)chr(10),'')23、如何在字符串里加回車或者tab鍵 在sqlplus中執行 sql>select 'UserId=1233111'chr(10)'AccId=13431'chr(9)'AccId2=11111' from dual;24、樹形查詢create table zj(bm;;number(8),bmmcvarchar2(20),sjbmnumber(8))insert into zj values(1,'aaa',0)insert into zj values(11,'aaa1',1)insert into zj values(12,'aaa2',1)insert into zj values(111,'aaa11',11)insert into zj values(112,'aaa12',11)insert into zj values(113,'aaa13',11)insert into zj values(121,'aaa21',12)insert into zj values(122,'aaa22',12)insert into zj values(123,'aaa23',12)--select bm,bmmc,sjbm,levelfrom zjstart with sjbm=0connect by prior; bm = sjbm或者select bm,bmmc,sjbm,levelfrom zjstart with sjbm=0connect by; sjbm = prior; bm 25、快照 create snapshot SNAPSHOT_NAME [storage (storage parameter)] [tablespace; TABLESPACE_NAME] [refresh; [fastcompleteforce] [start with; START_DATE next NEXT_DATE] as QUERY; create snapshot snapshot_to_study as select * from TABLE_NAME@to_study 創建角色 create role aa identified by aaa; 授權; grant create snapshot,alter snapshot to aaa; grant; aaa to emp; create snapshot SNAPSHOT_TO_Html refresh; complete start with sysdate next sysdate+5/(24*60*60) as; select * from a@to_html 刪除; drop snapshot snap_to_html 手工刷新快照,(調用DBMS_SNAPSHOT包中的refresh過程)DBMS_SNAPSHOT.refresh(snapshot_name,refresh_type); begin DBMS_SNAPSHOT.REFRESH('snap_to_html','c'); end; 對所有快照進行刷新 begin DBMS_SNAPSHOT.REFRESH_ALL; end; 怎樣執行遠程的內嵌過程 begin otherdbpro@to_html(參數); ;;;;end;26、用戶治理create a user: database authentication sql> create user juncky identified by oracle default tablespace users sql> temporary tablespace temp quota 10m on data password eXPire sql> [account lockunlock] [profile profilenamedefault]; ;<1>.查看當前用戶的缺省表空間SQL>select username,default_tablespace from user_users;<2>生成用戶時指定缺省表空間create user 用戶名 identified by 口令; default;;;tablespace 表空間名;<3>重新指定用戶的缺省表空間 ;;alter user 用戶名 default tablespace 表空間名<4>查看當前用戶的角色SQL>select * from user_role_privs;<5>查看當前用戶的系統權限和表級權限SQL>select * from user_sys_privs;SQL>select * from user_tab_privs;<6>查看用戶下所有的表 ;;SQL>select * from user_tables;<7> alter user語句的quota子句限制用戶的磁盤空間 ;;如:alter user jf; quota 10M; on system;27、查看放在ORACLE的內存區里的表;; ;SQL>select table_name,cache from user_tables where instr(cache,'Y')>0;28、約束條件 create table employee (empno; number(10); primary key, namevarchar2(40) not null, deptno; number(2); default 10, salary; number(7,2); check; salary<10000, birth_date date, soc_see_num; char(9); unique, foreign key(deptno) references dept.deptno) tablespace users; 要害字(primary key)必須是非空,表中記錄的唯一性 not null; 非空約束 default缺省值約束 check;;檢查約束,使列的值符合一定的標準范圍 unqiue; 唯一性約束 foreign key 外部鍵約束29、查看創建視圖的select語句 ;SQL>set view_name,text_length from user_views; ;SQL>set long 2000;;;說明：可以根據視圖的text_length值設定set long 的大小 ;SQL>select text from user_views where view_name=upper('&view_name');30、查看同義詞的名稱 ;SQL>select * from user_synonyms;31、用Sql語句實現查找一列中第N大值 select * from (select t.*,dense_rank() over (order by sal) rank from employee) where rank = N;32 虛擬自段 <1>. CURRVAL 和 nextval 為表創建序列 CREATE SEQUENCE EMPSEQ ... ; SELECT empseq.currval FROM DUAL ; 自動插入序列的數值 INSERT INTO emp VALUES (empseq.nextval, 'LEWIS', 'CLERK', 7902, SYSDATE, 1200, NULL, 20) ;<2>. ROWNUM ;按設定排序的行的序號 ;SELECT * FROM emp WHERE ROWNUM < 10 ;<3>. ROWID ;返回行的物理地址 ;SELECT ROWID, ename FROM emp; WHERE deptno = 20 ;33、對CLOB字段進行全文檢索SELECT * FROM A WHERE dbms_lob.instr(a.a,'K',1,1)>0;34. 非凡字符的插入，比如'&' insert into a values (translate ('at{&}t','at{}','at')); 35.表治理<1>.create a table sql> create table table_name (column datatype,column datatype]....) sql> tablespace tablespace_name [pctfree integer] [pctused integer] sql> [initrans integer] [maxtrans integer] sql> storage(initial 200k next 200k pctincrease 0 maxextents 50) sql> [loggingnologging] [cachenocache] ;<2>.copy an existing table sql> create table table_name [loggingnologging] as subquery <3> create table ... as 方式建表的時候，指定表參數 create table a storage( initial 1M/*第一次創建時分配空間*/ next 1M;;;/*第一次分配的存儲空間用完時在分配*/ ) as; select * from b;<4>.創建臨時表sql> create global temporary table xay_temp as select * from xay; on commit preserve rows/on commit delete rows 在Oracle中，可以創建以下兩種臨時表: a 會話特有的臨時表:create global temporary table () on commit preserve rows;會話指定，當中斷會話時ORACLE將截斷表b 事務特有的臨時表:create global temporary table () on commit delete rows;事務指定,每次提交后ORACLE將截斷表（刪除全部行） c 說明 臨時表只在當前連接內有效 臨時表不建立索引,所以假如數據量比較大或進行多次查詢時,不推薦使用 數據處理比較復雜的時候時表快,反之視圖快點 在僅僅查詢數據的時候建議用游標: open cursor for 'sql clause';<5> pctfree = (average row size - initial row size) *100 /average row size pctused = 100-pctfree- (average row size*100/available data space) <6>.change storage and block utilization parameter sql> alter table table_name pctfree=30 pctused=50 storage(next 500k sql> minextents 2 maxextents 100); ;<7>.manually allocating extents sql> alter table table_name allocate extent(size 500k datafile 'c:/oracle/data.dbf'); <8>.move tablespace sql> alter table employee move tablespace users; <9>.deallocate of unused space sql> alter table table_name deallocate unused [keep integer] <10>.drop a column sql> alter table table_name drop column comments cascade constraints checkpoint 1000; alter table table_name drop columns continue; <11>.mark a column as unused sql> alter table table_name set unused column comments cascade constraints; alter table table_name drop unused columns checkpoint 1000; alter table orders drop columns continue checkpoint 1000 data_dictionary : dba_unused_col_tabs37. 中文是如何排序的？ Oracle9i之前，中文是按照二進制編碼進行排序的。 在oracle9i中新增了按照拼音、部首、筆畫排序功能。設置NLS_SORT值 SCHINESE_RADICAL_M 按照部首（第一順序）、筆劃（第二順序）排序 SCHINESE_STROKE_M 按照筆劃（第一順序）、部首（第二順序）排序 SCHINESE_PINYIN_M 按照拼音排序 38. 數據表中的字段最大數:表或視圖中的最大列數為 100039. oracle中的裸設備: 裸設備就是繞過文件系統直接訪問的儲存空間40. 在Oracle服務器上通過SQLPLUS查看本機IP地址 ? select sys_context('userenv','ip_address') from dual; 假如是登陸本機數據庫，只能返回127.0.0.141. 在ORACLE中取毫秒? 9i之前不支持,9i開始有timestamp. 9i可以用select systimestamp from dual;42. 將N秒轉換為時分秒格式？ set serverout on declare N number := 1000000; ret varchar2(100); begin ret := trunc(n/3600) '小時' to_char(to_date(mod(n,3600),'sssss'),'fmmi'分'ss'秒'') ; dbms_output.put_line(ret); end; 43、在某個用戶下找所有的索引 select user_indexes.table_name, user_indexes.index_name,uniqueness, column_name from user_ind_columns, user_indexes where user_ind_columns.index_name = user_indexes.index_name and user_ind_columns.table_name = user_indexes.table_name order by user_indexes.table_type, user_indexes.table_name, user_indexes.index_name, column_position;44. not in的替代。 一般not in的效率比較低。非凡是數據量大的時候，幾乎不能執行。 用下面幾種方式可以替換寫法 比如要查詢在fee_rev_info表中已經銷戶的用戶（不在cm_user中的）(不過下面的例子不是很好，因為bill_id是cm_user的唯一索引） select * from fee_rev_info where bill_id not in (select bill_id from cm_user) <1> 用not exists select * from fee_rev_info a where not exists (select 'p' from cm_user b where b.bill_id = a.bill_id) <2> 用外連接(+)select a.* from fee_rev_info a,cm_user bwhere a.bill_id = b.bill_id (+)and b.bill_id is null <3> 用hash_aj select /*+HASH_AJ*/* from fee_rev_info where bill_id not in (select bill_id from cm_user)45.怎么樣查詢非凡字符，如通配符%與_ 假如數據庫中有表 STATIONTYPE,STATION_571 STATION_572 ... select * from tab; where tname like 'STATION_%'會顯示 STATIONTYPE,STATION_571 ... 可以用下面的語句select * from tab; where tname like 'STATION_%' escape''46.假如存在就更新，不存在就插入可以用一個語句實現嗎9i已經支持了，是Merge，但是只支持select子查詢，假如是單條數據記錄，可以寫作select .... from dual的子查詢。語法為：MERGE INTO tableUSING data_sourceON (condition)WHEN MATCHED THEN update_clauseWHEN NOT MATCHED THEN insert_clause;如MERGE INTO cm_user_credit; USING (select * from dual) ON (user_id =1302514690 )when MATCHED then update set credit_value = 1000when NOT MATCHED then insert (user_id,acc_id,bill_id,plan_id,region_code,credit_value) values(1302514690,1305032158,'13857141218',10070247,'571',1000);47.怎么實現一條記錄根據條件多表插入9i以上可以通過Insert all語句完成，僅僅是一個語句，如：INSERT ALLWHEN (id=1) THENINTO table_1 (id, name)values(id,name)WHEN (id=2) THENINTO table_2 (id, name)values(id,name)ELSEINTO table_other (id, name)values(id, name)SELECT id,nameFROM a;假如沒有條件的話，則完成每個表的插入，如INSERT ALLINTO table_1 (id, name)values(id,name)INTO table_2 (id, name)values(id,name)INTO table_other (id, name)values(id, name)SELECT id,nameFROM a;48.如何實現行列轉換<1>、固定列數的行列轉換如student subject grade---------------------------student1 語文 80student1 數學 70student1 英語 60student2 語文 90student2 數學 80student2 英語 100...轉換為 語文 數學 英語student1 80 70 60student2 90 80 100...語句如下：select student,sum(decode(subject,'語文', grade,null)) '語文',sum(decode(subject,'數學', grade,null)) '數學',sum(decode(subject,'英語', grade,null)) '英語'from tablegroup by student<2>、不定列行列轉換如c1 c2--------------1 我1 是1 誰2 知2 道3 不...轉換為1 我是誰2 知道3 不這一類型的轉換必須借助于PL/SQL來完成，這里給一個例子CREATE OR REPLACE FUNCTION get_c2(tmp_c1 NUMBER) RETURN VARCHAR2 IS Col_c2 VARCHAR2(4000); BEGINFOR cur IN (SELECT c2 FROM t WHERE c1=tmp_c1) LOOP Col_c2 := Col_c2cur.c2; END LOOP; Col_c2 := rtrim(Col_c2,1);RETURN Col_c2; END;/SQL> select distinct c1 ,get_c2(c1) cc2 from table;即可--例子：create table okcai_1(user_id varchar2(10),user_number varchar2(10),user_num number(8))user_id user_number user_num---------------------1;123 ;21;456 ;51;789 ;62;11; ;22;22; ;32;33; ;42;44; ;52;55; ;62;66; ;72;77; ;83;1234;13;5678;2方式一：create or replace function get_col( p_userId number, p_col;number) return varcharasv_tmp varchar2(255); begin select user_numberchr(9)user_num into v_tmp from (select user_number,user_num,rownum row_id from okcai_1 where user_id = p_userId) a where row_id = p_col; return ltrim(v_tmp); --return v_tmp;end;然后select distinct user_id,get_col(user_id,1),get_col(user_id,2),get_col(user_id,3) .... from okcai_1方式二：create or replace function get_col( p_userId number, p_col;number) return varcharasv_tmp varchar2(255);begin select user_numberchr(9)user_num into v_tmp from (select user_number,user_num,rownum row_id from okcai_1 where user_id = p_userId) a where row_id = p_col; return ltrim(v_tmp); --return v_tmp;end;select distinct user_id,get_col_new(user_id) from okcai_1;49.怎么設置存儲過程的調用者權限普通存儲過程都是所有者權限，假如想設置調用者權限，請參考如下語句create or replaceprocedure ...()AUTHID CURRENT_USERAsbegin...end;50.Oracle有哪些常見要害字具體信息可以查看v$reserved_words視圖51.怎么查看數據庫參數<1> show parameter 參數名如通過show parameter spfile可以查看9i是否使用spfile文件其中參數名是可以匹配的。比如show parameter cursor ,則會顯示跟cursor相關的參數<2>select * from v$parameter<3>除了這部分參數，Oracle還有大量隱含參數，可以通過如下語句查看:SELECT NAME ,VALUE ,decode(isdefault, 'TRUE','Y','N') as 'Default' ,decode(ISEM,'TRUE','Y','N') as SesMod ,decode(ISYM,'IMMEDIATE', 'I', 'DEFERRED', 'D', 'FALSE', 'N') as SysMod ,decode(IMOD,'MODIFIED','U', 'SYS_MODIFIED','S','N') as Modified ,decode(IADJ,'TRUE','Y','N') as Adjusted ,description FROM ( --GV$SYSTEM_PARAMETER SELECT x.inst_id as instance ,x.indx+1 ,ksppinm as NAME ,ksppity ,ksppstvl as VALUE ,ksppstdf as isdefault ,decode(bitand(ksppiflg/256,1),1,'TRUE','FALSE') as ISEM ,decode(bitand(ksppiflg/65536,3), 1,'IMMEDIATE',2,'DEFERRED','FALSE') as ISYM ,decode(bitand(ksppstvf,7),1,'MODIFIED','FALSE') as IMOD ,decode(bitand(ksppstvf,2),2,'TRUE','FALSE') as IADJ ,ksppdesc as DESCRIPTION FROM x$ksppi x ,x$ksppsv y WHERE x.indx = y.indx AND substr(ksppinm,1,1) = '_' AND x.inst_id = USERENV('Instance') ) ORDER BY NAME52.怎樣建立基于函數索引8i以上版本，確保Query_rewrite_enabled=trueQuery_rewrite_integrity=trustedCompatible=8.1.0以上Create index indexname on table (function(field));53.怎么樣移動表或表分區[A]移動表的語法Alter table tablename move[Tablespace new_name Storage(initial 50M next 50M pctincrease 0 pctfree 10 pctused 50 initrans 2) nologging]移動分區的語法alter table tablename move (partition partname)[update global indexes]之后之后必須重建索引Alter index indexname rebuild假如表有Lob段，那么正常的Alter不能移動Lob段到別的表空間，而僅僅是移動了表段，可以采用如下的方法移動Lob段alter table tablename move lob(lobsegname) store as (tablespace newts);54.怎么樣修改表的列名[A]9i以上版本可以采用rname命令ALTER TABLE UserName.TabName RENAME COLUMN SourceColumn TO DestColumn9i以下版本可以采用create table …… as select * from SourceTable的方式。另外，8i以上可以支持刪除列了ALTER TABLE UserName.TabName SET UNUSED (ColumnName) CASCADE CONSTRAINTSALTER TABLE UserName.TabName DROP (ColumnName) CASCADE CONSTRAINTS55.case的用法在sql語句中CASE test_valueWHEN expression1 THEN value1[[WHEN expression2 THEN value2] [...]][ELSE default_value]END 比如1SELECT last_name, job_id, salary CASE job_id WHEN 'IT_PROG' THEN 1.10*salary WHEN 'ST_CLERK' THEN 1.15*salary WHEN 'SA_REP' THEN 1.20*salary ELSE salary END 'REVISED_SALARY'FROM employees; 比如2select case when; real_charge>=20000 and real_charge<30000 then 5000 when; real_charge>=30000 and real_charge<40000 then 9000 when; real_charge>=40000 and real_charge<50000 then 10000 when; real_charge>=50000 and real_charge<60000 then 14000 when; real_charge>=60000 and real_charge<70000 then 18000 when; real_charge>=70000 and real_charge<80000 then 19000 when; real_charge>=80000 and real_charge<90000 then 24000 when; real_charge>=90000 and real_charge<100000 then 27000;;;;; when; real_charge>=100000 and real_charge<110000 then 27000 when; real_charge>=110000 and real_charge<120000 then 29000;;;; when; real_charge>=120000;;;then 36000 ;;;;;else 0; end ,acc_id,user_id,real_charge from okcai_jh_charge_200505在存儲過程中 case v_strGroupClassCode when; '1'then v_nAttrNum := v_nAttrNum + 300; v_strAttrFlag := '1'substr(v_strAttrFlag,2,7); when; '2'then v_nAttrNum := v_nAttrNum + 200; v_strAttrFlag := '2'substr(v_strAttrFlag,2,7); else NULL; end case;注重的是存儲過程和sql語句有的細微差別是用end case，而不是end。語句后面跟';'