oracle操作:oracle基本操作三来源: 发布时间:星期三, 2008年10月22日 浏览:11次 评论:0
.如何实现行列转换
<1>、固定列数的行列转换 如 student subject grade --------------------------- student1 语文 80 student1 数学 70 student1 英语 60 student2 语文 90 student2 数学 80 student2 英语 100 ... 转换为 语文 数学 英语 student1 80 70 60 student2 90 80 100 ... 语句如下: select student,sum(decode(subject,''''语文'''', grade,null)) "语文", sum(decode(subject,''''数学'''', grade,null)) "数学", sum(decode(subject,''''英语'''', grade,null)) "英语" from table group by student <2>、不定列行列转换 如 c1 c2 -------------- 1 我 1 是 1 谁 2 知 2 道 3 不 ... 转换为 1 我是谁 2 知道 3 不 这一类型的转换必须借助于PL/SQL来完成,Iy理M5i*nau1这里给一个例子 CREATE OR REPLACE FUNCTION get_c2(tmp_c1 NUMBER) RETURN VARCHAR2 IS Col_c2 VARCHAR2(4000); BEGIN FOR cur IN (SELECT c2 FROM t WHERE c1=tmp_c1) LOOP Col_c2 := Col_c2||cur.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 2 1 456 5 1 789 6 2 11 2 2 22 3 2 33 4 2 44 5 2 55 6 2 66 7 2 77 8 3 1234 1 3 5678 2 方式一: create or replace function get_col( p_userId number, p_col number ) return varchar as v_tmp varchar2(255); begin select user_number||chr(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 varchar as v_tmp varchar2(255); begin select user_number||chr(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.怎么设置存储过程的调用者权限 普通存储过程都是所有者权限,如果想设置调用者权限,请参考如下语句 create or replace procedure ...() AUTHID CURRENT_USER As begin ... end; 50.Oracle有哪些常见关键字 详细信息可以查看v$reserved_words视图 51.怎么查看数据库参数 <1> show parameter 参数名 如通过show parameter spfile可以查看9i是否使用spfile文件 其中参数名是可以匹配的。 比如show parameter cursor ,则会显示跟cursor相关的参数 <2> select * from v$parameter <3> 除了这部分参数,Oracle还有大量隐含参数,可以通过如下语句查看: 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$SYSTEM_PARAMETER SELECT x.inst_id as instance ,x.indx+1 ,ksppinm as NAME ,ksppity ,ksppstvl as VALUE ,ksppstdf as isdefault ,decode(bitand(ksppi***/256,1),1,''''TRUE'''',''''FALSE'''') as ISEM ,decode(bitand(ksppi***/65536,3), 1,''''IMMEDIATE'''',2,''''DEFERRED'''',''''FALSE'''') as ISYM ,decode(bitand(ksppstvf,7),1,''''MODIFIED'''',''''FALSE'''') as IMOD ,decode(bitand(ksppstvf,2),2,''''TRUE'''',''''FALSE'''') as IADJ ,ksppdesc as DESCRIPTION FROM x$ksppi x ,x$ksppsv y WHERE x.indx = y.indx AND substr(ksppinm,1,1) = ''''_'''' AND x.inst_id = USERENV(''''Instance'''') ) ORDER BY NAME 52.怎样建立基于函数索引 8i以上版本,确保 Query_rewrite_enabled=true Query_rewrite_integrity=trusted Compatible=8.1.0以上 Create index indexname on table (function(field)); 53.怎么样移动表或表分区 [A]移动表的语法 Alter table tablename move [Tablespace new_name Storage(initial 50M next 50M pctincrease 0 pctfree 10 pctused 50 initrans 2) nologging] 移动分区的语法 alter table tablename move (partition partname) [update global indexes] 之后之后必须重建索引 Alter index indexname rebuild 如果表有Lob段,那么正常的Alter不能移动Lob段到别的表空间,而仅仅是移动了表段,可以采用如下的方法移动Lob段 alter table tablename move lob(lobsegname) store as (tablespace newts); 54.怎么样修改表的列名 [A]9i以上版本可以采用rname命令 ALTER TABLE UserName.TabName RENAME COLUMN SourceColumn TO DestColumn 9i以下版本可以采用create table …… as select * from SourceTable的方式。 另外,8i以上可以支持删除列了 ALTER TABLE UserName.TabName SET UNUSED (ColumnName) CASCADE CONSTRAINTS ALTER TABLE UserName.TabName DROP (ColumnName) CASCADE CONSTRAINTS 55.case的用法 在sql语句中 CASE test_value WHEN expression1 THEN value1 [[WHEN expression2 THEN value2] [...]] [ELSE default_value] END 比如1 SELECT 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2 select 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 在存储过程中 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; 注意的是存储过程和sql语句有的细微差别是用end case,c$w+^G件nDR管{v的6而不是end。语句后面跟";" 0
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