第一篇:oracle復制表的sql語句
oracle復制表的sql語句
如下,表a是數據庫中已經存在的表,b是準備根據表a進行復制創建的表:
1、只復制表結構的sql
create table b as select * from a where 1<>12、即復制表結構又復制表中數據的sql
create table b as select * from a3、復制表的制定字段的sql
create table b as select row_id,name,age from a where 1<>1//前提是row_id,name,age都是a表的列
4、復制表的指定字段及這些指定字段的數據的sql
create table b as select row_id,name,age from a
以上語句雖然能夠很容易的根據a表結構復制創建b表,但是a表的索引等卻復制不了,需要在b中手動建立。
5、insert into 會將查詢結果保存到已經存在的表中
insert into t2(column1, column2,....)select column1, column2,....from t1rm_data001.dbf'
第二篇:oracle維護常用sql語句(主要)
1、oracle表空間利用率
SELECT UPPER(F.TABLESPACE_NAME)“表空間名”,D.TOT_GROOTTE_MB “表空間大小(M)”,D.TOT_GROOTTE_MBF.TOTAL_BYTES)D.TOT_GROOTTE_MB * 100,2),'990.99')||'%' “使用比(%)”,F.TOTAL_BYTES “空閑空間(M)”,F.MAX_BYTES “最大塊(M)”
FROM(SELECT TABLESPACE_NAME,ROUND(SUM(BYTES)/(1024 * 1024), 2)TOTAL_BYTES,ROUND(MAX(BYTES)/(1024 * 1024), 2)MAX_BYTES
FROM SYS.DBA_FREE_SPACE
GROUP BY TABLESPACE_NAME)F,(SELECT DD.TABLESPACE_NAME,ROUND(SUM(DD.BYTES)/(1024 * 1024), 2)TOT_GROOTTE_MB
FROM SYS.DBA_DATA_FILES DD
GROUP BY DD.TABLESPACE_NAME)D
WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME
ORDER BY F.TABLESPACE_NAME;查詢結果顯示:
/
非系統表空間使用和(M)
select sum(“已使用空間(M)”)“已使用空間(M)和” from(SELECT UPPER(F.TABLESPACE_NAME)“表空間名”,D.TOT_GROOTTE_MB “表空間大小(M)”,D.TOT_GROOTTE_MBF.TOTAL_BYTES)/ D.TOT_GROOTTE_MB * 100,2),'990.99')||'%' “使用比(%)”,F.TOTAL_BYTES “空閑空間(M)”,F.MAX_BYTES “最大塊(M)”
FROM(SELECT TABLESPACE_NAME,ROUND(SUM(BYTES)/(1024 * 1024), 2)TOTAL_BYTES,ROUND(MAX(BYTES)/(1024 * 1024), 2)MAX_BYTES
FROM SYS.DBA_FREE_SPACE
GROUP BY TABLESPACE_NAME)F,(SELECT DD.TABLESPACE_NAME,ROUND(SUM(DD.BYTES)/(1024 * 1024), 2)TOT_GROOTTE_MB
FROM SYS.DBA_DATA_FILES DD
GROUP BY DD.TABLESPACE_NAME)D
WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME and F.TABLESPACE_NAME NOT IN('SYSAUX','USERS','UNDOTBS1','SYSTEM'))
2、查詢當前用戶默認表空間的使用情況
select tablespacename,sum(totalContent),sum(usecontent),sum(sparecontent),avg(sparepercent)from(SELECT b.file_id as id,b.tablespace_name as tablespacename,b.bytes as totalContent,(b.bytes-sum(nvl(a.bytes,0)))as usecontent,sum(nvl(a.bytes,0))as sparecontent,sum(nvl(a.bytes,0))/(b.bytes)*100 as sparepercent FROM dba_free_space a,dba_data_files b WHERE a.file_id=b.file_id and b.tablespace_name =(select default_tablespace from dba_users where username = user)
group by b.tablespace_name,b.file_name,b.file_id,b.bytes)
GROUP BY tablespacename;
3、查詢所有用戶表使用大小的前三十名
select * from(select segment_name,bytes from dba_segments where owner = USER order by bytes desc)where rownum <= 30
4、查詢單張表的使用情況 select segment_name,bytes from dba_segments where segment_name = 'RE_STDEVT_FACT_DAY' and owner = USER
RE_STDEVT_FACT_DAY是您要查詢的表名稱
5、計算每個用戶占用的磁盤空間 select owner,sum(bytes)/1024/1024/1024 “Space(G)” from dba_segments group by owner order by 2;
6、計算某個用戶占用的磁盤空間
select owner,sum(bytes)/1024/1024/1024 “Space(G)” from dba_segments where owner='LIAOJL' group by owner;
7、查看表空間的名稱及大小(分配大小):
select t.tablespace_name, round(sum(bytes/(1024*1024)),0)ts_size
from dba_tablespaces t, dba_data_files d where t.tablespace_name = d.tablespace_name group by t.tablespace_name;
8、查看表空間物理文件的名稱及大小(分配大小):
select tablespace_name, file_id, file_name,round(bytes/(1024*1024),0)total_space from dba_data_files order by tablespace_name;
9、查看回滾段名稱及大小: select segment_name, tablespace_name, r.status,(initial_extent/1024)InitialExtent,(next_extent/1024)NextExtent, max_extents, v.curext CurExtent From dba_rollback_segs r, v$rollstat v Where r.segment_id = v.usn(+)order by segment_name;
10、如何查看某個回滾段里面,跑的什么事物或者正在執行什么sql語句: select d.sql_text,a.name from v$rollname a,v$transaction b,v$session c,v$sqltext d where a.usn=b.xidusn and b.addr=c.taddr and c.sql_address=d.address and c.sql_hash_value=d.hash_value and a.usn==2;(備注:你要看哪個,就把usn=?寫成幾就行了)
查看控制文件:
SQL>select * from v$controlfile;
查看日志文件:
SQL> col member format a50 SQL>select * from v$logfile;
11、如何查看當前SQL*PLUS用戶的sid和serial#:
SQL>select sid, serial#, status from v$session where audsid=userenv('sessionid');
12、怎樣識別IO競爭和負載平衡:
SQL>col 文件名 format a35 SQL>select df.name 文件名, fs.phyrds 讀次數, fs.phywrts 寫次數,(fs.readtim/decode(fs.phyrds,0,-1,fs.phyrds))讀時間,(fs.writetim/decode(fs.phywrts,0,-1,fs.phywrts))寫時間 from v$datafile df, v$filestat fs where df.file#=fs.file# order by df.name
13、查看有哪些用戶連接
select s.osuser os_user_name, decode(sign(48command), 1, to_char(command), 'Action Code #' || to_char(command))action, status session_status,s.osuser os_user_name,s.sid,p.spid ,s.serial# serial_num,nvl(s.username, '[Oracle process]')user_name,s.terminal terminal,s.program program,st.value criteria_value from v$sesstat st,v$session s , v$process p
where st.sid = s.sid and
st.statistic# = to_number('38')and
('ALL' = 'ALL' or s.status = 'ALL')and p.addr = s.paddr order by st.value desc, p.spid asc, s.username asc, s.osuser asc
21、監控當前數據庫誰在運行什么SQL語句: SELECT osuser, username, sql_text from v$session a, v$sqltext b where a.sql_address =b.address order by address, piece;
Column type format a8
22、查詢每個用戶執行過的sql語句 select B.USER_NAME,C.OSUSER,C.MACHINE,C.PROGRAM,C.MODULE, A.USER_IO_WAIT_TIME,B.HASH_VALUE,C.SERVICE_NAME, A.SQL_TEXT from v$sqlarea a, v$open_cursor b,v$session c where A.ADDRESS=B.ADDRESS and C.USERNAME=B.USER_NAME order by C.OSUSER,B.USER_NAME
第三篇:Oracle SQL精妙SQL語句講解
SQL*PLUS界面:
登錄:輸入SQLPLUS回車;輸入正確的ORACLE用戶名并回車;輸入用戶口令并回車,顯示提示符:SQL>
退出:輸入EXIT即可。
2)命令的編輯與運行:
在命令提示符后輸入SQL命令并運行,以分號結束輸入;以斜杠結束輸入;以空行結束輸入;
利用SQL緩沖區進行PL/SQL塊的編輯和運行;
利用命令文件進行PL/SQL塊的編輯和運行。
數據庫查詢
用SELECT語句從表中提取查詢數據。語法為
SELECT [DISTINCT] {column1,column2,…} FROM tablename WHERE {conditions} GROUP BY {conditions} ORDER BY {expressions} [ASC/DESC];
說明:SELECT子句用于指定檢索數據庫的中哪些列,FROM子句用于指定從哪一個表或視圖中檢索數據。
SELECT中的操作符及多表查詢WHERE子句。(LIKE,IS,…)
WHERE子句中的條件可以是一個包含等號或不等號的條件表達式,也可以是一個含有IN、NOT IN、BETWEEN、LIKE、IS NOT NULL等比較運算符的條件式,還可以是由單一的條件表達通過邏輯運算符組合成復合條件。
ORDER BY 子句
ORDER BY 子句使得SQL在顯示查詢結果時將各返回行按順序排列,返回行的排列順序由ORDER BY 子句指定的表達式的值確定。
連接查詢
利用SELECT語句進行數據庫查詢時,可以把多個表、視圖的數據結合起來,使得查詢結果的每一行中包含來自多個表達式或視圖的數據,這種操作被稱為連接查詢。
連接查詢的方法是在SELECT命令的FROM子句中指定兩個或多個將被連接查詢的表或視圖,并且在WHERE子句告訴ORACLE如何把多個表的數據進行合并。根據WHERE子句中的條件表達式是等還是不等式,可以把連接查詢分為等式連接和不等式連接。
子查詢
如果某一個SELECT命令(查詢1)出現在另一個SQL命令(查詢2)的一個子句中,則稱查詢1是查詢2的子查詢。
基本數據類型(NUMBER,VARCHAR2,DATE)O
RACEL支持下列內部數據類型:
VARCHAR2 變長字符串,最長為2000字符。
NUMBER 數值型。
LONG 變長字符數據,最長為2G字節。
DATE 日期型。
RAW 二進制數據,最長為255字節。
LONG RAW 變長二進制數據,最長為2G字節。
ROWID 二六進制串,表示表的行的唯一地址。
CHAR 定長字符數據,最長為255。
常用函數用法:
一個函數類似于一個算符,它操作數據項,返回一個結果。函數在格式上不同于算符,它個具有變元,可操作0個、一個、二個或多個變元,形式為:
函數名(變元,變元,…)
函數具有下列一般類形:
單行函數
分組函數
單行函數對查詢的表或視圖的每一行返回一個結果行。它有數值函數,字符函數,日期函數,轉換函數等。
分組函數返回的結果是基于行組而不是單行,所以分組函數不同于單行函數。在許多分組函數中可有下列選項:
DISTRNCT 該選項使分組函數只考慮變元表達式中的不同值。
ALL該選項使分組函數考慮全部值,包含全部重復。
全部分組函數(除COUNT(*)外)忽略空值。如果具有分組函數的查詢,沒有返回行或只有空值(分組函數的變元取值的行),則分組函數返回空值。
5、數據操縱語言命令:
數據庫操縱語言(DML)命令用于查詢和操縱模式對象中的數據,它不隱式地提交當前事務。它包含UPDATE、INSERT、DELETE、EXPLAIN PLAN、SELECT和LOCK TABLE 等命令。下面簡單介紹一下:
1)UPDATE tablename SET {column1=expression1,column2=expression2,…} WHERE {conditions};
例如:S QL>UPDATE EMP
SET JOB =’MANAGER’
WHERE ENAME=’MAPTIN’;
SQL >SELECT * FROM EMP;
UPDATE子句指明了要修改的數據庫是EMP,并用WHERE子句限制了只對名字(ENAME)為’MARTIN’的職工的數據進行修改,SET子句則說明修改的方式,即把’MARTION’的工作名稱(JOB)改為’MARAGER’.2)INSERT INTO tablename {column1,column2,…} VALUES {expression1,expression2,…};
例如:SQL>SELECT INTO DEPT(DNAME,DEPTNO)
VALUES(‘ACCOUNTING’,10)
3)DELETE FROM tablename WHERE {conditions};
例如:SQL>DELETE FROM EMP
WHERE EMPNO = 7654;
DELETE命令刪除一條記錄,而且DELETE命令只能刪除整行,而不能刪除某行中的部分數據.4)事務控制命令
提交命令(COMMIT):可以使數據庫的修改永久化.設置AUTOCOMMIT為允許狀態:SQL >SET AUTOCOMMIT ON;
回滾命令(ROLLBACK):消除上一個COMMIT命令后的所做的全部修改,使得數據庫的內容恢復到上一個COMMIT執行后的狀態.使用方法是:
SQL>ROLLBACK;
創建表、視圖、索引、同義詞、用戶。、表是存儲用戶數據的基本結構。
建立表主要指定義下列信息:
列定義
完整性約束
表所在表空間
存儲特性
可選擇的聚集
從一查詢獲得數據
語法如下:CREATE TABLE tablename
(column1 datatype [DEFAULT expression] [constraint], column1 datatype [DEFAULT expression] [constraint], ……)
[STORAGE子句] [其他子句…];
例如:
SQL>CREATE TABLE NEW_DEPT(DPTNO NUMBER(2), DNAME CHAR(6), LOC CHAR(13);
更改表作用:
增加列
增加完整性約束
重新定義列(數據類型、長度、缺省值)
修改存儲參數或其它參數
使能、使不能或刪除一完整性約束或觸發器
顯式地分配一個范圍
2)、視圖
視圖是一個邏輯表,它允許操作者從其它表或視圖存取數據,視圖本身不包含數據。視圖所基于的表稱為基表。
引入視圖有下列作用:
提供附加的表安全級,限制存取基表的行或/和列集合。
隱藏數據復雜性。
為數據提供另一種觀點。
促使ORACLE的某些操作在包含視圖的數據庫上執行,而不在另一個數據庫上執行。
3)、索引
索引是種數據庫對象。對于在表或聚集的索引列上的每一值將包含一項,為行提供直接的快速存取。在下列情況ORACLE可利用索引改進性能:
按指定的索引列的值查找行。
按索引列的順序存取表。
建立索引: CREATE [UNIQUE] INDEX indexname ON tablename(column ,。。);
例如:SQL>CREAT INDEX IC_EMP
ON CLUSTER EMPLOYEE
4)、同義詞
同義詞:為表、視圖、序列、存儲函數、包、快照或其它同義詞的另一個名字。使用同義詞為了安全和方便。對一對象建立同義詞可有下列好處:
引用對象不需指出對象的持有者。
引用對象不需指出它所位于的數據庫。
為對象提供另一個名字。
建立同義詞:
CREATE SYNONYM symnon_name FOR [username.]tablename;
例如:CREAT PUBLIC SYNONYM EMP
FOR SCOTT.EMP @SALES
5)、用戶
CREATE USER username IDENTIFIED BY password;
例如:SQL>CREATE USER SIDNEY
IDENTIFIED BY CARTON;
Oracle擴展PL/SQL簡介
PL/SQL概述。
PL/SQL是Oracle對SQL規范的擴展,是一種塊結構語言,即構成一個PL/SQL程序的基本單位(過程、函數和無名塊)是邏輯塊,可包含任何數目的嵌套了快。這種程序結構支持逐步求精方法解決問題。一個塊(或子塊)將邏輯上相關的說明和語句組合在一起,其形式為:
DECLARE
---說明
BEGIN
---語句序列
EXCEPTION
---例外處理程序
END;
它有以下優點:
支持SQL;
生產率高;
性能好;
可稱植性;
與ORACLE集成.PL/SQL體系結構
PL/SQL運行系統是種技術,不是一種獨立產品,可認為這種技術是PL/SQL塊和子程序的一種機,它可接收任何有效的PL/SQL塊或子程序。如圖所示:
PL/SQL機可執行過程性語句,而將SQL語句發送到ORACLE服務器上的SQL語句執行器。在ORACLE預編譯程序或OCI程序中可嵌入無名的PL/SQL塊。如果ORACLE具有PROCEDURAL選件,有名的PL/SQL塊(子程序)可單獨編譯,永久地存儲在數據庫中,準備執行。
PL/SQL基礎:
PL/SQL有一字符集、保留字、標點、數據類型、嚴密語法等,它與SQL有相同表示,現重點介紹。
1)、數據類型:如下表所示
數據類型 子類型
純量類型 數值 BINARY_INTEGER NATURAL,POSITIVE
NUMBER DEC,DECIMAL,DOUBLE PRECISION,PLOAT,INTEGER,INT,NUMERIC,REAL,SMALLINT
字符 CHAR CHARACTER,STRING
VARCHAR2 VARCHAR
LONG
LONG RAW
RAW
RAWID
邏輯 BOOLEAN
日期 DATE
組合 類型 記錄 RECORD
表 TABLE
2)、變量和常量
在PL/SQL程序中可將值存儲在變量和常量中,當程序執行時,變量的值可以改變,而常量的值不能改變。
3)、程序塊式結構:
DECLARE
變量說明部分;
BEGIN
執行語句部分;
[EXCEPTION
例外處理部分;] END;控制語句:
分支語句:
IF condition THEN
Sequence_of_statements;
END IF;
IF condition THEN
Sequence_of_statement1;
ELSE
Sequence_of_statement2;
END IF;
IF condition1 THEN
Sequence_of_statement1;
ELSIF condition2 THEN
Sequence_of_statement2;
ELSIF condition3 THEN
Sequence_of_statement3;
END IF;
循環語句:
LOOP
Sequence_of_statements;
IF condition THEN
EXIT;
END IF;
END LOOP;
WHILE condition LOOP
Sequence_of_statements;
END LOOP;
FOR counter IN lower_bound..higher_bound LOOP
Sequence_of_statements;
END LOOP;
子程序:
存儲過程:
CREATE PROCEDURE 過程名(參數說明1,參數說明2,[局部說明]
BEGIN
執行語句;
END 過程名;
。)IS。
存儲函數:
CREATE FUNCTION 函數名(參數說明1,參數說明2。。)RETURN 類型 IS [局部說明] BEGIN
執行語句;
END 函數名
Oracle SQL精妙SQL語句講解
好東西,大家趕緊收藏吧~~~
--行列轉換 行轉列
DROP TABLE t_change_lc;CREATE TABLE t_change_lc(card_code VARCHAR2(3), q NUMBER, bal NUMBER);
INSERT INTO t_change_lc
SELECT '001' card_code, ROWNUM q, trunc(dbms_random.VALUE * 100)bal FROM dual CONNECT BY ROWNUM <= 4 UNION
SELECT '002' card_code, ROWNUM q, trunc(dbms_random.VALUE * 100)bal FROM dual CONNECT BY ROWNUM <= 4;
SELECT * FROM t_change_lc;
SELECT a.card_code,SUM(decode(a.q, 1, a.bal, 0))q1,SUM(decode(a.q, 2, a.bal, 0))q2,SUM(decode(a.q, 3, a.bal, 0))q3,SUM(decode(a.q, 4, a.bal, 0))q4
FROM t_change_lc a GROUP BY a.card_code ORDER BY 1;
--行列轉換 列轉行
DROP TABLE t_change_cl;CREATE TABLE t_change_cl AS SELECT a.card_code,SUM(decode(a.q, 1, a.bal, 0))q1,SUM(decode(a.q, 2, a.bal, 0))q2,SUM(decode(a.q, 3, a.bal, 0))q3,SUM(decode(a.q, 4, a.bal, 0))q4
FROM t_change_lc a GROUP BY a.card_code ORDER BY 1;
SELECT * FROM t_change_cl;
SELECT t.card_code,t.rn q,decode(t.rn, 1, t.q1, 2, t.q2, 3, t.q3, 4, t.q4)bal
FROM(SELECT a.*, b.rn
FROM t_change_cl a,(SELECT ROWNUM rn FROM dual CONNECT BY ROWNUM <= 4)b)t ORDER BY 1, 2;
--行列轉換 行轉列 合并
DROP TABLE t_change_lc_comma;CREATE TABLE t_change_lc_comma AS SELECT card_code,'quarter_'||q AS q FROM t_change_lc;
SELECT * FROM t_change_lc_comma;
SELECT t1.card_code, substr(MAX(sys_connect_by_path(t1.q, ';')), 2)q
FROM(SELECT a.card_code,a.q,row_number()over(PARTITION BY a.card_code ORDER BY a.q)rn
FROM t_change_lc_comma a)t1 START WITH t1.rn = 1 CONNECT BY t1.card_code = PRIOR t1.card_code
AND t1.rn1 = PRIOR t1.rn GROUP BY t1.card_code;
SELECT * FROM t_change_cl_comma;SELECT t.card_code,substr(t.q,instr(';' || t.q, ';', 1, rn),instr(t.q || ';', ';', 1, rn)-instr(';' || t.q, ';', 1, rn))q
FROM(SELECT a.card_code, a.q, b.rn
FROM t_change_cl_comma a,(SELECT ROWNUM rn FROM dual CONNECT BY ROWNUM <= 100)b
WHERE instr(';' || a.q, ';', 1, rn)> 0)t ORDER BY 1, 2;
--實現一條記錄根據條件多表插入 DROP TABLE t_ia_src;CREATE TABLE t_ia_src AS SELECT 'a'||ROWNUM c1, 'b'||ROWNUM c2 FROM dual CONNECT BY ROWNUM<=5;DROP TABLE t_ia_dest_1;CREATE TABLE t_ia_dest_1(flag VARCHAR2(10), c VARCHAR2(10));DROP TABLE t_ia_dest_2;CREATE TABLE t_ia_dest_2(flag VARCHAR2(10), c VARCHAR2(10));DROP TABLE t_ia_dest_3;CREATE TABLE t_ia_dest_3(flag VARCHAR2(10), c VARCHAR2(10));
SELECT * FROM t_ia_src;SELECT * FROM t_ia_dest_1;SELECT * FROM t_ia_dest_2;SELECT * FROM t_ia_dest_3;
INSERT ALL WHEN(c1 IN('a1','a3'))THEN
INTO t_ia_dest_1(flag,c)VALUES(flag1,c2)WHEN(c1 IN('a2','a4'))THEN
INTO t_ia_dest_2(flag,c)VALUES(flag2,c2)ELSE INTO t_ia_dest_3(flag,c)VALUES(flag1||flag2,c1||c2)SELECT c1,c2, 'f1' flag1, 'f2' flag2 FROM t_ia_src;
--如果存在就更新,不存在就插入用一個語句實現 DROP TABLE t_mg;CREATE TABLE t_mg(code VARCHAR2(10), NAME VARCHAR2(10));
SELECT * FROM t_mg;
MERGE INTO t_mg a USING(SELECT 'the code' code, 'the name' NAME FROM dual)b ON(a.code = b.code)WHEN MATCHED THEN
UPDATE SET a.NAME = b.NAME WHEN NOT MATCHED THEN
INSERT(code, NAME)VALUES(b.code, b.NAME);
--抽取/刪除重復記錄
DROP TABLE t_dup;CREATE TABLE t_dup AS SELECT 'code_'||ROWNUM code, dbms_random.string('z',5)NAME FROM dual CONNECT BY ROWNUM<=10;
INSERT INTO t_dup SELECT 'code_'||ROWNUM code, dbms_random.string('z',5)NAME FROM dual CONNECT BY ROWNUM<=2;
SELECT * FROM t_dup;
SELECT * FROM t_dup a WHERE a.ROWID <>(SELECT MIN(b.ROWID)FROM t_dup b WHERE a.code=b.code);
SELECT b.code, b.NAME
FROM(SELECT a.code,a.NAME,row_number()over(PARTITION BY a.code ORDER BY a.ROWID)rn
FROM t_dup a)b WHERE b.rn > 1;
--IN/EXISTS的不同適用環境--t_orders.customer_id有索引 SELECT a.*
FROM t_employees a WHERE a.employee_id IN
(SELECT b.sales_rep_id FROM t_orders b WHERE b.customer_id = 12);
SELECT a.*
FROM t_employees a WHERE EXISTS(SELECT 1
FROM t_orders b
WHERE b.customer_id = 12
AND a.employee_id = b.sales_rep_id);
--t_employees.department_id有索引 SELECT a.*
FROM t_employees a WHERE a.department_id = 10
AND EXISTS(SELECT 1 FROM t_orders b WHERE a.employee_id = b.sales_rep_id);
SELECT a.*
FROM t_employees a WHERE a.department_id = 10
AND a.employee_id IN(SELECT b.sales_rep_id FROM t_orders b);
--FBI DROP TABLE t_fbi;CREATE TABLE t_fbi AS SELECT ROWNUM rn, dbms_random.STRING('z',10)NAME , SYSDATE + dbms_random.VALUE * 10 dt FROM dual
CONNECT BY ROWNUM <=10;
CREATE INDEX idx_nonfbi ON t_fbi(dt);
DROP INDEX idx_fbi_1;CREATE INDEX idx_fbi_1 ON t_fbi(trunc(dt));
SELECT * FROM t_fbi WHERE trunc(dt)= to_date('2006-09-21','yyyy-mm-dd');
--不建議使用
SELECT * FROM t_fbi WHERE to_char(dt, 'yyyy-mm-dd')= '2006-09-21';
--LOOP中的COMMIT/ROLLBACK DROP TABLE t_loop PURGE;create TABLE t_loop AS SELECT * FROM user_objects WHERE 1=2;
SELECT * FROM t_loop;
--逐行提交 DECLARE BEGIN
FOR cur IN(SELECT * FROM user_objects)LOOP
INSERT INTO t_loop VALUES cur;
COMMIT;
END LOOP;END;
--模擬批量提交 DECLARE
v_count NUMBER;BEGIN
FOR cur IN(SELECT * FROM user_objects)LOOP
INSERT INTO t_loop VALUES cur;
v_count := v_count + 1;
IF v_count >= 100 THEN
COMMIT;
END IF;
END LOOP;
COMMIT;END;
--真正的批量提交 DECLARE
CURSOR cur IS
SELECT * FROM user_objects;
TYPE rec IS TABLE OF user_objects%ROWTYPE;
recs rec;BEGIN
OPEN cur;
WHILE(TRUE)LOOP
FETCH cur BULK COLLECT
INTO recs LIMIT 100;
--forall 實現批量
FORALL i IN 1..recs.COUNT
INSERT INTO t_loop VALUES recs(i);
COMMIT;
EXIT WHEN cur%NOTFOUND;
END LOOP;
CLOSE cur;END;
--悲觀鎖定/樂觀鎖定
DROP TABLE t_lock PURGE;CREATE TABLE t_lock AS SELECT 1 ID FROM dual;
SELECT * FROM t_lock;
--常見的實現邏輯,隱含bug DECLARE
v_cnt NUMBER;BEGIN
--這里有并發性的bug
SELECT MAX(ID)INTO v_cnt FROM t_lock;
--here for other operation
v_cnt := v_cnt + 1;
INSERT INTO t_lock(ID)VALUES(v_cnt);
COMMIT;END;
--高并發環境下,安全的實現邏輯 DECLARE
v_cnt NUMBER;BEGIN
--對指定的行取得lock
SELECT ID INTO v_cnt FROM t_lock WHERE ID=1 FOR UPDATE;
--在有lock的情況下繼續下面的操作
SELECT MAX(ID)INTO v_cnt FROM t_lock;
--here for other operation
v_cnt := v_cnt + 1;
INSERT INTO t_lock(ID)VALUES(v_cnt);
COMMIT;--提交并且釋放lock END;
--硬解析/軟解析
DROP TABLE t_hard PURGE;CREATE TABLE t_hard(ID INT);
SELECT * FROM t_hard;
DECLARE
sql_1
VARCHAR2(200);BEGIN
--hard parse
--java中的同等語句是 Statement.execute()
FOR i IN 1..1000 LOOP
sql_1 := 'insert into t_hard(id)values(' || i || ')';
EXECUTE IMMEDIATE sql_1;
END LOOP;
COMMIT;
--soft parse
--java中的同等語句是 PreparedStatement.execute()
sql_1
:= 'insert into t_hard(id)values(:id)';
FOR i IN 1..1000 LOOP
EXECUTE IMMEDIATE sql_1
USING i;
END LOOP;
COMMIT;END;
--正確的分頁算法
SELECT *
FROM(SELECT a.*, ROWNUM rn
FROM(SELECT * FROM t_employees ORDER BY first_name)a
WHERE ROWNUM <= 500)WHERE rn > 480;
--分頁算法(why not this one)SELECT a.*, ROWNUM rn
FROM(SELECT * FROM t_employees ORDER BY first_name)a WHERE ROWNUM <= 500 AND ROWNUM > 480;
--分頁算法(why not this one)SELECT b.*
FROM(SELECT a.*, ROWNUM rn
FROM t_employees a
WHERE ROWNUM < = 500
ORDER BY first_name)b WHERE b.rn > 480;
--OLAP--小計合計 SELECT CASE
WHEN a.deptno IS NULL THEN
'合計'
WHEN a.deptno IS NOT NULL AND a.empno IS NULL THEN
'小計'
ELSE
'' || a.deptno
END deptno,a.empno,a.ename,SUM(a.sal)total_sal
FROM scott.emp a GROUP BY GROUPING SETS((a.deptno),(a.deptno, a.empno, a.ename),());
--分組排序 SELECT a.deptno,a.empno,a.ename,a.sal,--可跳躍的rank
rank()over(PARTITION BY a.deptno ORDER BY a.sal DESC)r1,--密集型rank
dense_rank()over(PARTITION BY a.deptno ORDER BY a.sal DESC)r2,--不分組排序
rank()over(ORDER BY sal DESC)r3
FROM scott.emp a
ORDER BY a.deptno,a.sal DESC;
--當前行數據和前/后n行的數據比較 SELECT a.empno,a.ename,a.sal,--上面一行
lag(a.sal)over(ORDER BY a.sal DESC)lag_1,--下面三行
lead(a.sal, 3)over(ORDER BY a.sal DESC)lead_3
FROM scott.emp a ORDER BY a.sal DESC;
一、數據表設計圖
二、創建語句
/*================*/ /* DBMS name: ORACLE Version 9i */ /* Created on: 2008-11-10 23:39:24 */ /*================*/
alter table “emp”
drop constraint FK_EMP_REFERENCE_DEPT;
drop table “dept” cascade constraints;
drop table “emp” cascade constraints;
drop table “salgrade” cascade constraints;
/*================*/ /* Table: “dept” */ /*================*/
create table dept(deptno NUMBER(11)not null, dname VARCHAR2(15)not null, loc VARCHAR2(15)not null, constraint PK_DEPT primary key(deptno));
/*================*/ /* Table: “emp” */ /*================*/
create table emp(empno NUMBER(11)not null, deptno NUMBER(11), ename VARCHAR2(15)not null, sal NUMBER(11)not null, job VARCHAR2(15)not null, mgr NUMBER(11)not null, hirdate DATE not null, comm NUMBER(11)not null, constraint PK_EMP primary key(empno));
/*================*/ /* Table: salgrade */ /*================*/
create table salgrade(grade NUMBER(11)not null, losal NUMBER(11)not null, hisal NUMBER(11)not null, constraint PK_SALGRADE primary key(grade));
alter table emp add constraint FK_EMP_REFERENCE_DEPT foreign key(deptno)references dept(deptno);
三、測試要求及語句
/** *公司工資最高的員工列表 子查詢 */
select t.ename,t.sal from emp t where t.sal =(select max(sal)from emp)
/** *查詢每一個員工的經理人及自己的名字 */
select e1.ename,e2.ename from emp e1 join emp e2 on(e1.mgr = e2.empno)
/** *查詢公司平均薪水的等級 */
select s.grade from salgrade s where(select avg(t.sal)from emp t)between s.losal and s.hisal
/** *求部門中那些人的工資最高 */
select d.dname,ename,sal from(select t.deptno,ename,sal from(select deptno,max(sal)as max_sal from emp group by deptno)e join emp t on(e.deptno = t.deptno and t.sal = max_sal))et join dept d on(d.deptno = et.deptno)
/** *查詢部門平均薪水的等級 */
select d.dname,avg_sal,grade from(select deptno,avg_sal,grade from(select deptno,avg(sal)as avg_sal from emp group by deptno)e join salgrade s on(e.avg_sal between s.losal and s.hisal))es join dept d on(es.deptno = d.deptno)
/** *求部門的平均薪水等級 */
select deptno,avg(grade)from(select deptno,grade from emp e join salgrade s on(e.sal between s.losal and s.hisal))t group by t.deptno
/** * 求那些人是經理人 */
select ename from emp e where empno in(select distinct mgr from emp)
/** *不準用組函數 求薪水的最高值 */
select ename from emp where empno not in(select distinct e1.empno from emp e1 join emp e2 on(e1.sal /** *平均薪水最高的部門編號與名稱 */ select d.deptno,dname from(select deptno,avg(sal)avg_sal from emp group by deptno)t1 join dept d on(d.deptno = t1.deptno)where avg_sal =(select max(avg_sal)from(select deptno,avg(sal)avg_sal from emp group by deptno)t2) /** *求平均薪水的等級最低的部門名稱 */ select dname from dept d where d.deptno in(select deptno from(select deptno,grade from(select deptno,avg(sal)avg_sal from emp group by deptno)t1 join salgrade g on(avg_sal between g.losal and g.hisal))t2 where t2.grade =(select min(grade)from(select deptno,grade from(select deptno,avg(sal)avg_sal from emp group by deptno)t1 join salgrade g on(avg_sal between g.losal and g.hisal))t3)) /** *求部門經理人中平均薪水最低的部門名稱 */ select d.dname,t1.avg_sal from dept d join(select deptno,avg(sal)avg_sal from(select e2.deptno,e2.ename,e2.sal from emp e1 join emp e2 on(e1.mgr = e2.empno))t group by deptno)t1 on(d.deptno = t1.deptno)where avg_sal =(select min(avg_sal)from(select deptno,avg(sal)avg_sal from(select e2.deptno,e2.ename,e2.sal from emp e1 join emp e2 on(e1.mgr = e2.empno))t group by deptno))/** *求必普通員工的最高薪水還要高的經理人名稱 */ select ename from(select e2.ename,e2.empno,e2.sal from emp e1 join emp e2 on(e1.mgr = e2.empno))t where t.sal >(select max(e.sal)from emp e where e.empno not in(select e1.mgr from emp e1 join emp e2 on(e1.mgr = e2.empno))) /** *求薪水最高的第6名到10名雇員 */ SELECT * FROM(SELECT A.*, ROWNUM RN FROM(SELECT * FROM(select e1.ename,e1.sal from emp e1 order by e1.sal desc))A WHERE ROWNUM <= 10)WHERE RN >= 6 好東西,大家趕緊收藏吧~~~ 轉自junsansi --行列轉換 行轉列 DROP TABLE t_change_lc;CREATE TABLE t_change_lc(card_code VARCHAR2(3), q NUMBER, bal NUMBER); INSERT INTO t_change_lc SELECT '001' card_code, ROWNUM q, trunc(dbms_random.VALUE * 100)bal FROM dual CONNECT BY ROWNUM <= 4 UNION SELECT '002' card_code, ROWNUM q, trunc(dbms_random.VALUE * 100)bal FROM dual CONNECT BY ROWNUM <= 4; SELECT * FROM t_change_lc; SELECT a.card_code,SUM(decode(a.q, 1, a.bal, 0))q1,SUM(decode(a.q, 2, a.bal, 0))q2,SUM(decode(a.q, 3, a.bal, 0))q3,SUM(decode(a.q, 4, a.bal, 0))q4 FROM t_change_lc a GROUP BY a.card_code ORDER BY 1; --行列轉換 列轉行 DROP TABLE t_change_cl;CREATE TABLE t_change_cl AS SELECT a.card_code,SUM(decode(a.q, 1, a.bal, 0))q1,SUM(decode(a.q, 2, a.bal, 0))q2,SUM(decode(a.q, 3, a.bal, 0))q3,SUM(decode(a.q, 4, a.bal, 0))q4 FROM t_change_lc a GROUP BY a.card_code ORDER BY 1; SELECT * FROM t_change_cl; SELECT t.card_code,t.rn q,decode(t.rn, 1, t.q1, 2, t.q2, 3, t.q3, 4, t.q4)bal FROM(SELECT a.*, b.rn FROM t_change_cl a,(SELECT ROWNUM rn FROM dual CONNECT BY ROWNUM <= 4)b)t ORDER BY 1, 2; --行列轉換 行轉列 合并 DROP TABLE t_change_lc_comma;CREATE TABLE t_change_lc_comma AS SELECT card_code,'quarter_'||q AS q FROM t_change_lc; SELECT * FROM t_change_lc_comma; SELECT t1.card_code, substr(MAX(sys_connect_by_path(t1.q, ';')), 2)q FROM(SELECT a.card_code,a.q,row_number()over(PARTITION BY a.card_code ORDER BY a.q)rn FROM t_change_lc_comma a)t1 START WITH t1.rn = 1 CONNECT BY t1.card_code = PRIOR t1.card_code AND t1.rn1 = PRIOR t1.rn GROUP BY t1.card_code; SELECT * FROM t_change_cl_comma; SELECT t.card_code,substr(t.q,instr(';' || t.q, ';', 1, rn),instr(t.q || ';', ';', 1, rn)-instr(';' || t.q, ';', 1, rn))q FROM(SELECT a.card_code, a.q, b.rn FROM t_change_cl_comma a,(SELECT ROWNUM rn FROM dual CONNECT BY ROWNUM <= 100)b WHERE instr(';' || a.q, ';', 1, rn)> 0)t ORDER BY 1, 2; --實現一條記錄根據條件多表插入 DROP TABLE t_ia_src;CREATE TABLE t_ia_src AS SELECT 'a'||ROWNUM c1, 'b'||ROWNUM c2 FROM dual CONNECT BY ROWNUM<=5;DROP TABLE t_ia_dest_1;CREATE TABLE t_ia_dest_1(flag VARCHAR2(10), c VARCHAR2(10));DROP TABLE t_ia_dest_2;CREATE TABLE t_ia_dest_2(flag VARCHAR2(10), c VARCHAR2(10));DROP TABLE t_ia_dest_3;CREATE TABLE t_ia_dest_3(flag VARCHAR2(10), c VARCHAR2(10)); SELECT * FROM t_ia_src;SELECT * FROM t_ia_dest_1;SELECT * FROM t_ia_dest_2;SELECT * FROM t_ia_dest_3; INSERT ALL WHEN(c1 IN('a1','a3'))THEN INTO t_ia_dest_1(flag,c)VALUES(flag1,c2)WHEN(c1 IN('a2','a4'))THEN INTO t_ia_dest_2(flag,c)VALUES(flag2,c2)ELSE INTO t_ia_dest_3(flag,c)VALUES(flag1||flag2,c1||c2)SELECT c1,c2, 'f1' flag1, 'f2' flag2 FROM t_ia_src; --如果存在就更新,不存在就插入用一個語句實現 DROP TABLE t_mg;CREATE TABLE t_mg(code VARCHAR2(10), NAME VARCHAR2(10)); SELECT * FROM t_mg; MERGE INTO t_mg a USING(SELECT 'the code' code, 'the name' NAME FROM dual)b ON(a.code = b.code)WHEN MATCHED THEN UPDATE SET a.NAME = b.NAME WHEN NOT MATCHED THEN INSERT(code, NAME)VALUES(b.code, b.NAME); --抽取/刪除重復記錄 DROP TABLE t_dup;CREATE TABLE t_dup AS SELECT 'code_'||ROWNUM code, dbms_random.string('z',5)NAME FROM dual CONNECT BY ROWNUM<=10;INSERT INTO t_dup SELECT 'code_'||ROWNUM code, dbms_random.string('z',5)NAME FROM dual CONNECT BY ROWNUM<=2; SELECT * FROM t_dup; SELECT * FROM t_dup a WHERE a.ROWID <>(SELECT MIN(b.ROWID)FROM t_dup b WHERE a.code=b.code); SELECT b.code, b.NAME FROM(SELECT a.code,a.NAME,row_number()over(PARTITION BY a.code ORDER BY a.ROWID)rn FROM t_dup a)b WHERE b.rn > 1; --IN/EXISTS的不同適用環境--t_orders.customer_id有索引 SELECT a.* FROM t_employees a WHERE a.employee_id IN (SELECT b.sales_rep_id FROM t_orders b WHERE b.customer_id = 12); SELECT a.* FROM t_employees a WHERE EXISTS(SELECT 1 FROM t_orders b WHERE b.customer_id = 12 AND a.employee_id = b.sales_rep_id); --t_employees.department_id有索引 SELECT a.* FROM t_employees a WHERE a.department_id = 10 AND EXISTS(SELECT 1 FROM t_orders b WHERE a.employee_id = b.sales_rep_id); SELECT a.* FROM t_employees a WHERE a.department_id = 10 AND a.employee_id IN(SELECT b.sales_rep_id FROM t_orders b);--FBI DROP TABLE t_fbi;CREATE TABLE t_fbi AS SELECT ROWNUM rn, dbms_random.STRING('z',10)NAME , SYSDATE + dbms_random.VALUE * 10 dt FROM dual CONNECT BY ROWNUM <=10; CREATE INDEX idx_nonfbi ON t_fbi(dt); DROP INDEX idx_fbi_1;CREATE INDEX idx_fbi_1 ON t_fbi(trunc(dt)); SELECT * FROM t_fbi WHERE trunc(dt)= to_date('2006-09-21','yyyy-mm-dd'); --不建議使用 SELECT * FROM t_fbi WHERE to_char(dt, 'yyyy-mm-dd')= '2006-09-21'; --LOOP中的COMMIT/ROLLBACK DROP TABLE t_loop PURGE;create TABLE t_loop AS SELECT * FROM user_objects WHERE 1=2; SELECT * FROM t_loop; --逐行提交 DECLARE BEGIN FOR cur IN(SELECT * FROM user_objects)LOOP INSERT INTO t_loop VALUES cur; COMMIT;END LOOP;END; --模擬批量提交 DECLARE v_count NUMBER;BEGIN FOR cur IN(SELECT * FROM user_objects)LOOP INSERT INTO t_loop VALUES cur; v_count := v_count + 1; IF v_count >= 100 THEN COMMIT; END IF;END LOOP;COMMIT;END; --真正的批量提交 DECLARE CURSOR cur IS SELECT * FROM user_objects;TYPE rec IS TABLE OF user_objects%ROWTYPE;recs rec;BEGIN OPEN cur;WHILE(TRUE)LOOP FETCH cur BULK COLLECT INTO recs LIMIT 100; --forall 實現批量 FORALL i IN 1..recs.COUNT INSERT INTO t_loop VALUES recs(i); COMMIT; EXIT WHEN cur%NOTFOUND;END LOOP;CLOSE cur;END; --悲觀鎖定/樂觀鎖定 DROP TABLE t_lock PURGE;CREATE TABLE t_lock AS SELECT 1 ID FROM dual; SELECT * FROM t_lock; --常見的實現邏輯,隱含bug DECLARE v_cnt NUMBER;BEGIN--這里有并發性的bug SELECT MAX(ID)INTO v_cnt FROM t_lock; --here for other operation v_cnt := v_cnt + 1;INSERT INTO t_lock(ID)VALUES(v_cnt);COMMIT;END; --高并發環境下,安全的實現邏輯 DECLARE v_cnt NUMBER;BEGIN--對指定的行取得lock SELECT ID INTO v_cnt FROM t_lock WHERE ID=1 FOR UPDATE;--在有lock的情況下繼續下面的操作 SELECT MAX(ID)INTO v_cnt FROM t_lock; --here for other operation v_cnt := v_cnt + 1;INSERT INTO t_lock(ID)VALUES(v_cnt);COMMIT;--提交并且釋放lock END; --硬解析/軟解析 DROP TABLE t_hard PURGE;CREATE TABLE t_hard(ID INT); SELECT * FROM t_hard; DECLARE sql_1 VARCHAR2(200);BEGIN--hard parse--java中的同等語句是 Statement.execute()FOR i IN 1..1000 LOOP sql_1 := 'insert into t_hard(id)values(' || i || ')'; EXECUTE IMMEDIATE sql_1;END LOOP;COMMIT; --soft parse--java中的同等語句是 PreparedStatement.execute()sql_1 := 'insert into t_hard(id)values(:id)';FOR i IN 1..1000 LOOP EXECUTE IMMEDIATE sql_1 USING i;END LOOP;COMMIT;END; --正確的分頁算法 SELECT * FROM(SELECT a.*, ROWNUM rn FROM(SELECT * FROM t_employees ORDER BY first_name)a WHERE ROWNUM <= 500)WHERE rn > 480; --分頁算法(why not this one)SELECT a.*, ROWNUM rn FROM(SELECT * FROM t_employees ORDER BY first_name)a WHERE ROWNUM <= 500 AND ROWNUM > 480; --分頁算法(why not this one)SELECT b.* FROM(SELECT a.*, ROWNUM rn FROM t_employees a WHERE ROWNUM < = 500 ORDER BY first_name)b WHERE b.rn > 480;--OLAP--小計合計 SELECT CASE WHEN a.deptno IS NULL THEN '合計' WHEN a.deptno IS NOT NULL AND a.empno IS NULL THEN '小計' ELSE '' || a.deptno END deptno,a.empno,a.ename,SUM(a.sal)total_sal FROM scott.emp a GROUP BY GROUPING SETS((a.deptno),(a.deptno, a.empno, a.ename),()); --分組排序 SELECT a.deptno,a.empno,a.ename,a.sal,--可跳躍的rank rank()over(PARTITION BY a.deptno ORDER BY a.sal DESC)r1,--密集型rank dense_rank()over(PARTITION BY a.deptno ORDER BY a.sal DESC)r2,--不分組排序 rank()over(ORDER BY sal DESC)r3 FROM scott.emp a ORDER BY a.deptno,a.sal DESC;--當前行數據和前/后n行的數據比較 SELECT a.empno,a.ename,a.sal,--上面一行 lag(a.sal)over(ORDER BY a.sal DESC)lag_1,--下面三行 lead(a.sal, 3)over(ORDER BY a.sal DESC)lead_3 FROM scott.emp a ORDER BY a.sal DESC; 查詢Oracle正在執行和執行過的SQL語句 --正在執行的select a.username, a.sid,b.SQL_TEXT, b.SQL_FULLTEXT from v$session a, v$sqlarea bwhere a.sql_address = b.address ---執行過的select b.SQL_TEXT,b.FIRST_LOAD_TIME,b.SQL_FULLTEXT from v$sqlarea b where b.FIRST_LOAD_TIME between '2009-10-15/09:24:47' and'2009-10-15/09:24:47' order by b.FIRST_LOAD_TIME (此方法好處可以查看某一時間段執行過的sql,并且 SQL_FULLTEXT 包含了完整的 sql 語句)其他 select OSUSER,PROGRAM,USERNAME,SCfrom V$SESSION A LEFT JOIN V$SQL B ON A.SQL_ADDRESS=B.ADDRESS AND A.SQL_HASH_VALUE=B.HASH_VALUE order by b.cpu_time desc HEMANAME,B.Cpu_Time,STATUS,B.SQL_TEXTselect address, sql_text, piece from v$session, v$sqltextwhere address = sql_address --and machine = < you machine name >order by address, piece 查找前十條性能差的sql.SELECT * FROM(select PARSING_USER_ID,EXECUTIONS,SORTS,COMMAND_TYPE,DISK_READS,sql_text FROM v$sqlarea order BY disk_reads DESC)where ROWNUM<10; 查看占io較大的正在運行的sessionfacebook:http:// SELECT se.sid,se.serial#,pr.SPID,se.username,se.status,se.terminal,se.program,se.MODULE,、se.sql_address,st.event,st.p1text,si.physical_reads,si.block_changes FROM v$session se,v$session_wait st,v$sess_io si,v$process pr WHERE st.sid=se.sid AND st.sid=si.sid AND se.PADDR=pr.ADDR AND se.sid>6 AND st.wait_time=0 AND st.event NOT LIKE '%SQL%' ORDER BY physical_reads DESC第四篇:Oracle SQL精妙SQL語句講解
第五篇:查詢Oracle正在執行和執行過的SQL語句