oracle常用sql语句(不断更新中)
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C:\>sqlplus "system/manager@orcl"SQL*Plus: Release 10.2.0.1.0 - Production on 星期日 1月 5 19:30:54 2014Copyright (c) 1982, 2005, Oracle. All rights reserved.连接到:Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - ProductionWith the Partitioning, OLAP and Data Mining options
显示当前连接用户:
SQL> show userUSER 为 "SYSTEM"
查看系统拥有哪些用户:
SQL> select * from all_users;USERNAME USER_ID CREATED------------------------------ ---------- --------------USER1 61 01-1月 -14BI 60 01-1月 -14PM 59 01-1月 -14SH 58 01-1月 -14IX 57 01-1月 -14OE 56 01-1月 -14HR 55 01-1月 -14SCOTT 54 30-8月 -05MGMT_VIEW 53 30-8月 -05MDDATA 50 30-8月 -05SYSMAN 51 30-8月 -05USERNAME USER_ID CREATED------------------------------ ---------- --------------MDSYS 46 30-8月 -05SI_INFORMTN_SCHEMA 45 30-8月 -05ORDPLUGINS 44 30-8月 -05ORDSYS 43 30-8月 -05OLAPSYS 47 30-8月 -05ANONYMOUS 39 30-8月 -05XDB 38 30-8月 -05CTXSYS 36 30-8月 -05EXFSYS 34 30-8月 -05WMSYS 25 30-8月 -05DBSNMP 24 30-8月 -05USERNAME USER_ID CREATED------------------------------ ---------- --------------TSMSYS 21 30-8月 -05DMSYS 35 30-8月 -05DIP 19 30-8月 -05OUTLN 11 30-8月 -05SYSTEM 5 30-8月 -05SYS 0 30-8月 -05已选择28行。
新建用户并授权:
SQL> CREATE USER USER1 2 IDENTIFIED BY USER1 3 DEFAULT TABLESPACE USERS 4 TEMPORARY TABLESPACE TEMP 5 PROFILE DEFAULT;用户已创建。SQL> GRANT CONNECT,RESOURCE TO USER1;授权成功。
连接到用户user1:
SQL> CONN USER1/USER1;已连接。
创建表:
SQL> CREATE TABLE TB1(ID INTEGER PRIMARY KEY);表已创建。
查询表结构:
SQL> DESC TB1; 名称 是否为空? 类型 ----------------------------------------- -------- ---------------------------- ID NOT NULL NUMBER(38)
修改用户密码:
SQL> ALTER USER USER1 IDENTIFIED BY USER1;用户已更改。
增加字段:
SQL> ALTER TABLE TB1 ADD (USERNAME VARCHAR2(10) NULL);表已更改。SQL> DESC TB1; 名称 是否为空? 类型 ----------------------------------------- -------- ---------------------------- ID NOT NULL NUMBER(38) USERNAME VARCHAR2(10)
修改字段:
SQL> ALTER TABLE TB1 MODIFY (USERNAME VARCHAR2(20));表已更改。
创建索引:
SQL> CREATE INDEX TB1_USERNAME_INDEX ON TB1 (USERNAME);索引已创建。
删除索引:
SQL> DROP INDEX TB1_USERNAME_INDEX;索引已删除。
删除字段:
SQL> ALTER TABLE TB1 DROP (USERNAME);表已更改。
删除表:
SQL> DROP TABLE TB1;表已删除。
删除用户:
SQL> CONN SYSTEM/MANAGER已连接。SQL> DROP USER USER1;用户已删除。
创建主键自增长的表:
CREATE TABLE TB_STUDENT ( ID INTEGER PRIMARY KEY, STUDENT_NAME VARCHAR2(20) NULL);
CREATE SEQUENCE SE_STUDENTSTART WITH 1INCREMENT BY 1CACHE 20NOMAXVALUE;
CREATE OR REPLACE TRIGGER TRI_STUDENTBEFORE INSERT ON TB_STUDENT FOR EACH ROWBEGIN SELECT SE_STUDENT.NEXTVAL INTO:NEW.ID FROM DUAL;END;
存储过程(不带参数):
CREATE OR REPLACE PROCEDURE PRO_PRINT ASSTUDENT_COUNT INTEGER;BEGIN SELECT COUNT(1) INTO STUDENT_COUNT FROM TB_STUDENT; IF STUDENT_COUNT>1 THEN DBMS_OUTPUT.PUT_LINE(STUDENT_COUNT); ELSE DBMS_OUTPUT.PUT_LINE('no student found'); END IF;END;
执行存储过程:
BEGIN PRO_PRINT;END;
或者用CALL,一定要加括号:
CALL PRO_STUDENT_INSERT();
随机数函数:
1、dbms_random.normal
这个函数不带参数,能返回normal distribution的一个number类型,所以基本上随机数会在-1到1之间。
2、dbms_random.random
这个也没有参数,返回一个从-power(2,31)到power(2,31)的整数值
3、dbms_random.value
这个函数分为两种,一种是没有参数,则直接返回0-1之间的38位小数
第二种是加上两个参数a、b,则返回值在a、b之间的38位小数
4、dbms_random.string
这个函数必须带有两个参数,前面的字符指定类型,后面的数值指定位数(最大60)
类型说明:
'u','U' : upper case alpha characters only
'l','L' : lower case alpha characters only
'a','A' : alpha characters only (mixed case)
'x','X' : any alpha-numeric characters (upper)
'p','P' : any printable characters
随机数函数测试:
CREATE OR REPLACE PROCEDURE PRO_RANDOM(RANDOM_FROM IN INTEGER, RANDOM_TO IN INTEGER, RANDOM_STRING OUT VARCHAR2)ASRANDOM_RANDOM INTEGER;RANDOM_NORMAL INTEGER;RANDOM_VALUE INTEGER;BEGIN SELECT DBMS_RANDOM.RANDOM INTO RANDOM_RANDOM FROM DUAL; SELECT DBMS_RANDOM.NORMAL INTO RANDOM_NORMAL FROM DUAL; IF RANDOM_FROM > RANDOM_TO THEN SELECT DBMS_RANDOM.VALUE(RANDOM_TO, RANDOM_FROM) INTO RANDOM_VALUE FROM DUAL; ELSE SELECT DBMS_RANDOM.VALUE(RANDOM_FROM, RANDOM_TO) INTO RANDOM_VALUE FROM DUAL; END IF; SELECT DBMS_RANDOM.STRING('U', 20) INTO RANDOM_STRING FROM DUAL; DBMS_OUTPUT.PUT_LINE('RANDOM_RANDOM='||RANDOM_RANDOM); DBMS_OUTPUT.PUT_LINE('RANDOM_NORMAL='||RANDOM_NORMAL); DBMS_OUTPUT.PUT_LINE('RANDOM_VALUE='||RANDOM_VALUE); DBMS_OUTPUT.PUT_LINE('RANDOM_STRING='||RANDOM_STRING);END;
执行:
DECLARERANDOM_FROM INTEGER;RANDOM_TO INTEGER;RANDOM_STRING_OUT VARCHAR2(20);BEGIN RANDOM_FROM:=1; RANDOM_TO:=100; PRO_RANDOM(RANDOM_FROM,RANDOM_TO, RANDOM_STRING_OUT); DBMS_OUTPUT.PUT_LINE('RANDOM_STRING_OUT='||RANDOM_STRING_OUT);END;
结果(每次都不同):
RANDOM_RANDOM=-33085305RANDOM_NORMAL=-1RANDOM_VALUE=17RANDOM_STRING=MADGMQSZXJAHWPJNMWCSRANDOM_STRING_OUT=MADGMQSZXJAHWPJNMWCS
获得系统时间:
SELECT SYSDATE FROM DUAL
输出:
2014-1-13 22:42:38
格式化时间:
SELECT TO_CHAR(SYSDATE, 'yyyy-MM-dd HH24:mi:ss') FROM DUAL
输出:
2014-01-13 22:43:29
SELECT TO_DATE('2013-01-04 12:12:12', 'yyyy-MM-dd HH24:mi:ss') FROM DUAL;
输出:
2013-1-4 12:12:12
存储过程循环插入数据:
CREATE OR REPLACE PROCEDURE PRO_STUDENT_INSERT ASBEGIN FOR I IN 1..10000 LOOP INSERT INTO TB_STUDENT (STUDENT_NAME) VALUES ('aaa'); END LOOP;END;
执行:
BEGIN PRO_STUDENT_INSERT;END;
用游标遍历数据:
DECLARECURSOR C1 IS SELECT STUDENT_NAME FROM TB_STUDENT;BEGIN FOR STUDENT_ROW IN C1 LOOP DBMS_OUTPUT.PUT_LINE(STUDENT_ROW.STUDENT_NAME); END LOOP;END;
IN和EXISTS性能比较:
插入100万条数据:
CREATE OR REPLACE PROCEDURE PRO_STUDENT_INSERT ASRANDOM_STRING VARCHAR2(20);BEGIN FOR I IN 1..1000000 LOOP SELECT DBMS_RANDOM.STRING('U', 20) INTO RANDOM_STRING FROM DUAL; INSERT INTO TB_STUDENT (STUDENT_NAME) VALUES (RANDOM_STRING); END LOOP;END;
BEGIN PRO_STUDENT_INSERT;END;
显示执行时间:
set timing on
另外创建两张表:
CREATE TABLE TB_STU1 AS SELECT * FROM TB_STUDENT WHERE ID >= 32500 AND ID <= 102800;CREATE TABLE TB_STU2 AS SELECT * FROM TB_STUDENT WHERE ID >= 32500 AND ID <= 102800;
不创建索引,执行:
SQL> SELECT COUNT(STUDENT_NAME) FROM TB_STUDENT A WHERE EXISTS (SELECT STUDENT_NAME FROM TB_STU1 B WHERE A.STUDENT_NAME=B.STUDENT_NAME);COUNT(STUDENT_NAME)------------------- 70301已用时间: 00: 00: 01.56SQL> SELECT COUNT(STUDENT_NAME) FROM TB_STUDENT WHERE STUDENT_NAME IN (SELECT STUDENT_NAME FROM TB_STU2);COUNT(STUDENT_NAME)------------------- 70301已用时间: 00: 00: 00.70SQL>
网上说EXISTS比IN好,可是结果IN更快,后来多测试了几次:
CREATE TABLE TB_STU1 AS SELECT * FROM TB_STUDENT WHERE ID >= 150000 AND ID <= 260000;CREATE TABLE TB_STU2 AS SELECT * FROM TB_STUDENT WHERE ID >= 150000 AND ID <= 260000;
结果:
SELECT STUDENT_NAME FROM TB_STUDENT A WHERE EXISTS (SELECT STUDENT_NAME FROM TB_STU1 B WHERE A.STUDENT_NAME=B.STUDENT_NAME);已用时间: 00: 00: 22.45SELECT STUDENT_NAME FROM TB_STUDENT WHERE STUDENT_NAME IN (SELECT STUDENT_NAME FROM TB_STU2);已用时间: 00: 00: 15.64
有几次,时间是差不多的,但是IN快的次数更多。
现在创建索引:
CREATE INDEX IDX1 ON TB_STU1(STUDENT_NAME);CREATE INDEX IDX2 ON TB_STU2(STUDENT_NAME);CREATE INDEX IDX ON TB_STUDENT(STUDENT_NAME);
测试结果:
当外面是TB_STUDENT的时候,IN比EXISTS快。
SELECT STUDENT_NAME FROM TB_STUDENT A WHERE EXISTS (SELECT STUDENT_NAME FROM TB_STU1 B WHERE A.STUDENT_NAME=B.STUDENT_NAME);已用时间: 00: 05: 11.90SELECT STUDENT_NAME FROM TB_STUDENT WHERE STUDENT_NAME IN (SELECT STUDENT_NAME FROM TB_STU2);已用时间: 00: 02: 24.50
当里面是TB_STUDENT的时候,EXISTS比IN快。
SELECT STUDENT_NAME FROM TB_STU1 A WHERE EXISTS (SELECT STUDENT_NAME FROM TB_STUDENT B WHERE A.STUDENT_NAME=B.STUDENT_NAME);已用时间: 00: 01: 43.53SELECT STUDENT_NAME FROM TB_STU2 WHERE STUDENT_NAME IN (SELECT STUDENT_NAME FROM TB_STUDENT);已用时间: 00: 03: 56.59
TB_STUDENT的数据多,其他表数据少,不过,经过多次测试,并非每次都这样。
性能测试:SELECT * 和SELECT 字段名
插入100万条数据
CREATE TABLE TB_STUDENT ( ID INTEGER PRIMARY KEY, STUDENT_NAME VARCHAR2(20) NOT NULL, SEX VARCHAR2(1) NOT NULL, AGE INTEGER NOT NULL);CREATE SEQUENCE SE_STUDENTSTART WITH 1INCREMENT BY 1CACHE 20NOMAXVALUE;CREATE OR REPLACE TRIGGER TRI_STUDENTBEFORE INSERT ON TB_STUDENT FOR EACH ROWBEGIN SELECT SE_STUDENT.NEXTVAL INTO:NEW.ID FROM DUAL;END;CREATE OR REPLACE PROCEDURE PRO_STUDENT_INSERT ASBEGIN FOR I IN 1..1000000 LOOP IF I <= 10000 THEN INSERT INTO TB_STUDENT (STUDENT_NAME, SEX, AGE) VALUES ('aaaaa', 'B', 11); ELSIF I<=100000 THEN INSERT INTO TB_STUDENT (STUDENT_NAME, SEX, AGE) VALUES ('bbbbb', 'G', 12); ELSIF I<=500000 THEN INSERT INTO TB_STUDENT (STUDENT_NAME, SEX, AGE) VALUES ('ccccc', 'B', 13); ELSE INSERT INTO TB_STUDENT (STUDENT_NAME, SEX, AGE) VALUES ('ddddd', 'G', 14); END IF; END LOOP; COMMIT;END;CALL PRO_STUDENT_INSERT();
测试结果:
SELECT * FROM TB_STUDENT WHERE ID <= 100000;已用时间: 00: 00: 32.92SELECT ID, STUDENT_NAME, SEX, AGE FROM TB_STUDENT WHERE ID <= 100000;已用时间: 00: 00: 32.50SELECT * FROM TB_STUDENT WHERE ID >= 100001 AND ID <=200000;已用时间: 00: 00: 25.12SELECT ID, STUDENT_NAME, SEX, AGE FROM TB_STUDENT WHERE ID >= 100001 AND ID <=200000;已用时间: 00: 00: 24.45SELECT * FROM TB_STUDENT;已用时间: 00: 03: 34.21SELECT ID, STUDENT_NAME, SEX, AGE FROM TB_STUDENT;已用时间: 00: 01: 53.95SELECT * FROM TB_STUDENT;已用时间: 00: 02: 14.85SELECT ID, STUDENT_NAME, SEX, AGE FROM TB_STUDENT;已用时间: 00: 02: 04.62
上面看到查100万条记录,第二次时间远远比第一次少,这是因为缓存的关系,下面清理一下缓存:
ALTER SYSTEM FLUSH BUFFER_CACHE;
再次测试:
SELECT * FROM TB_STUDENT;已用时间: 00: 03: 22.29SELECT ID, STUDENT_NAME, SEX, AGE FROM TB_STUDENT;已用时间: 00: 02: 47.64
看到直接写出字段名和用*,显然是直接写字段名快,但是快了没多少。
多测试几次,每次都清缓存,如下:
SELECT * FROM TB_STUDENT;已用时间: 00: 02: 15.59SELECT ID, STUDENT_NAME, SEX, AGE FROM TB_STUDENT;已用时间: 00: 02: 14.17SELECT * FROM TB_STUDENT;已用时间: 00: 02: 24.21SELECT ID, STUDENT_NAME, SEX, AGE FROM TB_STUDENT;已用时间: 00: 02: 18.48
然后增加10列再测试一下:
ALTER TABLE TB_STUDENT ADD ( COL1 VARCHAR2(10) NULL, COL2 VARCHAR2(10) NULL, COL3 VARCHAR2(10) NULL, COL4 VARCHAR2(10) NULL, COL5 VARCHAR2(10) NULL, COL6 VARCHAR2(10) NULL, COL7 VARCHAR2(10) NULL, COL8 VARCHAR2(10) NULL, COL9 VARCHAR2(10) NULL, COL10 VARCHAR2(10) NULL);
测试结果:
SELECT * FROM TB_STUDENT;已用时间: 00: 06: 16.53SELECT ID, STUDENT_NAME, SEX, AGE, COL1, COL2, COL3, COL4, COL5, COL6, COL7, COL8, COL9, COL10 FROM TB_STUDENT;已用时间: 00: 06: 00.76SELECT * FROM TB_STUDENT;已用时间: 00: 05: 52.68SELECT ID, STUDENT_NAME, SEX, AGE, COL1, COL2, COL3, COL4, COL5, COL6, COL7, COL8, COL9, COL10 FROM TB_STUDENT;已用时间: 00: 06: 18.56
所以,感觉两条SQL语句,并没有很明显的时间上的差别,也就30秒左右的差别。测试数据量是100万条。
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