1. Oracle11g Database SQL 语言基础 2011.8 By Kevinlin. 林少杰 [email_address]

4. 查询数据

5. 使用 SELECT 查询数据 表 1 表 2 查询表中的若干行数据 查询表中的若干列 联合不同表 中的数据

7. 查询所有列 SELECT * FROM departments;

8. 查询指定列 SELECT department_id, location_id FROM departments;

10. SELECT 语句中的四则运算 SELECT last_name, salary, 12*(salary+100) FROM employees;

17. DESCRIBE 命令 DESCRIBE employees

20. 使用比较运算符 SELECT last_name, salary FROM employees WHERE salary <= 3000 ;

34. SQL 函数 SQL functions 函数 输入 参数 1 参数 2 参数 n 函数进行运算 输出 结果

35. SQL 函数的两种类型 单行函数 多行函数 每行返回一个结果 多行返回一个结果 函数

37. 字符函数 Character Functions 字符函数 LOWER UPPER INITCAP CONCAT SUBSTR LENGTH INSTR LPAD | RPAD TRIM REPLACE 大小写转换函数 字符处理函数

38. 大小写转换函数 Case-Conversion sql course LOWER('SQL Course') Sql Course INITCAP('SQL Course') SQL COURSE UPPER('SQL Course') 结果 函数

39. 字符处理函数 BLACK and BLUE REPLACE ('JACK and JUE','J','BL') 10 LENGTH('HelloWorld') 6 INSTR('HelloWorld', 'W') *****24000 LPAD(salary,10,'*') 24000***** RPAD(salary, 10, '*') HelloWorld CONCAT('Hello', 'World') elloWorld TRIM('H' FROM 'HelloWorld') Hello SUBSTR('HelloWorld',1,5) 结果 函数

40. 数字函数 100 MOD(1600, 300) 45.93 ROUND(45.926, 2) 45.92 TRUNC(45.926, 2) 结果 函数

41. 日期函数 '08-SEP-95' NEXT_DAY ('01-SEP-95','FRIDAY') '28-FEB-95' LAST_DAY ('01-FEB-95') 19.6774194 MONTHS_BETWEEN ('01-SEP-95','11-JAN-94') ‘ 29-FEB-96' ADD_MONTHS (‘31-JAN-96',1) Result Function 01-JUL-03 TRUNC(SYSDATE ,'MONTH') 01-JAN-03 TRUNC(SYSDATE ,'YEAR') 01-AUG-03 ROUND(SYSDATE,'MONTH') 01-JAN-04 ROUND(SYSDATE ,'YEAR')

42. 转换函数 隐式转换 显式转换 数据类型转换

43. 数据类型的隐式转换 NUMBER VARCHAR2 or CHAR DATE VARCHAR2 or CHAR To From VARCHAR2 or CHAR NUMBER VARCHAR2 or CHAR DATE To From … where hire_date > '01-JAN-90' … where name_varchar > 2345 不建议使用隐式转换，可能导致 SQL 的性能下降

44. 数据类型的显式转换 数字类型 字符类型 TO_CHAR() TO_NUMBER() 日期类型 TO_CHAR() TO_DATE()

45. 日期转换为字符 SELECT last_name, TO_CHAR(hire_date, 'fmDD Month YYYY') AS HIREDATE FROM employees; …

46. 数字转换为字符 SELECT TO_CHAR(salary, '$99,999.00') SALARY FROM employees WHERE last_name = 'Ernst';

47. 字符转换为日期、数字 SQL> select TO_number('6,000.00','99,999.00') from dual; TO_NUMBER('6,000.00','99,999.00') --------------------------------- 6000 SQL> select TO_date('20110818','YYYYMMDD') from dual; TO_DATE('201 ------------ 18-AUG-11

53. 数据分组 GROUP BY 表 EMPLOYEES … 在 EMPLOYEES 表中，计算每个部门的平均工资 SELECT column , group_function(column) FROM table [WHERE condition ] [GROUP BY group_by_expression ] [ORDER BY column ]; 4400 9500 3500 6400 10033

54. 多个列的 GROUP BY SELECT department_id dept_id, job_id, SUM(salary) FROM employees GROUP BY department_id, job_id ORDER BY department_id;

57. 组函数的嵌套 SELECT MAX(AVG(salary)) FROM employees GROUP BY department_id;

58. 多个表的数据查询

63. 使用 ON 进行 join SELECT employee_id, city, department_name FROM employees e JOIN departments d ON d.department_id = e.department_id JOIN locations l ON d.location_id = l.location_id; …

66. 非对等连接 Nonequijoins SELECT e.last_name, e.salary, j.grade_level FROM employees e JOIN job_grades j ON e.salary BETWEEN j.lowest_sal AND j.highest_sal; …

67. 外连接 Outer Joins EMPLOYEES DEPARTMENTS There are no employees in department 190. …

69. 左外连接 Left Outer Join SELECT e.last_name, e.department_id, d.department_name FROM employees e LEFT OUTER JOIN departments d ON (e.department_id = d.department_id) ; …

70. 全外连接 Left Outer Join SELECT e.last_name, d.department_id, d.department_name FROM employees e FULL OUTER JOIN departments d ON (e.department_id = d.department_id) ; …

78. 集合操作符 Set Operators UNION / UNION ALL A B A B A B INTERSECT A B MINUS

80. UNION SELECT employee_id, job_id FROM employees UNION SELECT employee_id, job_id FROM job_history; … …

81. UNION ALL SELECT employee_id, job_id, department_id FROM employees UNION ALL SELECT employee_id, job_id, department_id FROM job_history ORDER BY employee_id; … …

82. INTERSECT SELECT employee_id, job_id FROM employees INTERSECT SELECT employee_id, job_id FROM job_history;

83. MINUS SELECT employee_id FROM employees MINUS SELECT employee_id FROM job_history; …

84. 列数量与类型匹配 SELECT location_id , department_name &quot;Department&quot; , TO_CHAR(NULL) &quot;Warehouse location&quot; FROM departments UNION SELECT location_id, TO_CHAR(NULL) &quot;Department&quot; , state_province FROM locations;

86. 多列子查询 Multiple-Column Subqueries 主查询 WHERE ( MANAGER_ID, DEPARTMENT_ID ) IN 子查询结果 100 90 102 60 124 50

88. 成对比较子查询 返回与名字为 John 的员工在同一个部门，且同一个领导的员工 SELECT employee_id, manager_id, department_id FROM empl_demo WHERE (manager_id, department_id) IN (SELECT manager_id, department_id FROM empl_demo WHERE first_name = 'John') AND first_name <> 'John';

89. 不成对比较子查询 返回与名字为 John 的员工中任意一个领导相符和任意一个部门相符的员工 当名字为 John 多于一人时，与成对比较子查询的返回结果不同。 SELECT employee_id, manager_id, department_id FROM empl_demo WHERE manager_id IN (SELECT manager_id FROM empl_demo WHERE first_name = 'John') AND department_id IN (SELECT department_id FROM empl_demo WHERE first_name = 'John') AND first_name <> 'John';

90. 关联子查询 关联子查询用于行与行的处理，关联子查询对每个数据行都要进行 一次。 GET 主查询 fetch 到一行数据 EXECUTE 子查询根据这行数据的值进行运算 USE 根据子查询的结果，决定是否返回这行数据

91. 关联子查询 vs 嵌套子查询 嵌套子查询： 子查询首先执行，且执行一次，返回相关结果 主查询使用子查询返回的结果进行一次运算 关联子查询： 主查询 fetch 到一行数据 根据这行数据，进行子查询运算 根据子查询的结果，决定是否返回这行数据 重复以上过程，直到主查询结束

92. 使用关联子查询 SELECT column1 , column2 , ... FROM table1 WHERE column1 operator (SELECT column1, column2 FROM table2 WHERE expr1 = .expr2 ); outer outer SELECT e.employee_id, last_name,e.job_id FROM employees e WHERE 2 <= (SELECT COUNT(*) FROM job_history WHERE employee_id = e.employee_id );

94. WITH 示例 WITH dept_costs AS ( SELECT d.department_name, SUM(e.salary) AS dept_total FROM employees e JOIN departments d ON e.department_id = d.department_id GROUP BY d.department_name), avg_cost AS ( SELECT SUM(dept_total)/COUNT(*) AS dept_avg FROM dept_costs ) SELECT * FROM dept_costs WHERE dept_total > (SELECT dept_avg FROM avg_cost ) ORDER BY department_name;

95. 处理数据

97. INSERT INSERT INTO departments VALUES (100, 'Finance', NULL, NULL); INSERT INTO departments (department_id, department_name) VALUES (30, 'Purchasing'); INSERT INTO sales_reps(id, name, salary, commission_pct) SELECT employee_id, last_name, salary, commission_pct FROM employees INSERT INTO employees (employee_id,hire_date) VALUES (113,SYSDATE);

99. Unconditional INSERT ALL INSERT ALL INTO sal_history VALUES(EMPID,HIREDATE,SAL) INTO mgr_history VALUES(EMPID,MGR,SAL) SELECT employee_id EMPID, hire_date HIREDATE, salary SAL, manager_id MGR FROM employees WHERE employee_id > 200;

100. Unconditional INSERT ALL INSERT ALL INTO sal_history VALUES(EMPID,HIREDATE,SAL) INTO mgr_history VALUES(EMPID,MGR,SAL) SELECT employee_id EMPID, hire_date HIREDATE, salary SAL, manager_id MGR FROM employees WHERE employee_id > 200;

101. Conditional INSERT ALL INSERT ALL WHEN HIREDATE < ' 01-JAN-95 ' THEN INTO emp_history VALUES(EMPID,HIREDATE,SAL) WHEN COMM IS NOT NULL THEN INTO emp_sales VALUES(EMPID,COMM,SAL) SELECT employee_id EMPID, hire_date HIREDATE, salary SAL, commission_pct COMM FROM employees

102. Conditional INSERT FIRST INSERT FIRST WHEN salary < 5000 THEN INTO sal_low VALUES (employee_id, last_name, salary) WHEN salary between 5000 and 10000 THEN INTO sal_mid VALUES (employee_id, last_name, salary) ELSE INTO sal_high VALUES (employee_id, last_name, salary) SELECT employee_id, last_name, salary FROM employees

104. Pivoting INSERT INSERT ALL INTO sales_info VALUES (employee_id,week_id,sales_MON) INTO sales_info VALUES (employee_id,week_id,sales_TUE) INTO sales_info VALUES (employee_id,week_id,sales_WED) INTO sales_info VALUES (employee_id,week_id,sales_THUR) INTO sales_info VALUES (employee_id,week_id, sales_FRI) SELECT EMPLOYEE_ID, week_id, sales_MON, sales_TUE, sales_WED, sales_THUR,sales_FRI FROM sales_source_data;

105. UPDATE UPDATE employees SET department_id = 50 WHERE employee_id = 113; UPDATE copy_emp SET department_id = 110; UPDATE employees SET department_id = 50 WHERE employee_id = null; UPDATE employees SET job_id = (SELECT job_id FROM employees WHERE employee_id = 205) WHERE employee_id = 113;

106. UPDATE 中的关联子查询 UPDATE table1 alias1 SET column = (SELECT expression FROM table2 alias2 WHERE alias1.column = alias2.column );

107. DELETE DELETE FROM departments WHERE department_name = ‘Finance'; DELETE FROM copy_emp; DELETE FROM employees WHERE department_id = (SELECT department_id FROM departments WHERE department_name LIKE '%Public%');

108. DELETE 中的关联子查询 DELETE FROM table1 alias1 WHERE column operator (SELECT expression FROM table2 alias2 WHERE alias1.column = alias2.column);

112. 事务的显式控制 SAVEPOINT B SAVEPOINT A DELETE INSERT UPDATE INSERT COMMIT 时间轴 Transaction ROLLBACK to SAVEPOINT B ROLLBACK to SAVEPOINT A ROLLBACK

118. 读一致性的实现 SELECT * FROM userA.employees; UPDATE employees SET salary = 7000 WHERE last_name = 'Grant'; Data blocks Undo segments Changed and unchanged data Before change (“old” data) 用户 A 用户 B Read- consistent image

120. 创建数据库对象

121. 数据库对象 逻辑上代表一个或多个表的数据子集 View 产生单调递增的数值 Sequence 存放数据行的逻辑存储单元 Table 同义词，一个对象的替代名称 Synonym 用于改进查询性能 Index 描述 对象

124. CREATE TABLE DESCRIBE dept CREATE TABLE dept (deptno NUMBER(2), dname VARCHAR2(14), loc VARCHAR2(13), create_date DATE DEFAULT SYSDATE );

125. 引用其他用户的表 USERB USERA SELECT * FROM userB.employees; SELECT * FROM userA.employees;

126. CTAS (Create Table As Select) CREATE TABLE dept80 AS SELECT employee_id, last_name, salary*12 ANNSAL, hire_date FROM employees WHERE department_id = 80; DESCRIBE dept80

127. 数据类型 未经处理的类型 RAW and LONG RAW 二进制数据类型 (up to 4 GB) BLOB 存储在外部文件的二进制数据类型 (up to 4 GB) BFILE 日期类型 DATE 变长的字符类型 (up to 2 GB) LONG 字符类型 (up to 4 GB) CLOB 代表表中数据行的唯一地址 ROWID 定长的字符数据 CHAR( size ) 变长的数值类型 NUMBER( p , s) 变长的字符类型 VARCHAR2( size ) 描述 Data Type

128. 数据类型 存储时间间隔的类型 INTERVAL YEAR TO MONTH 存储时间间隔的类型 INTERVAL DAY TO SECOND 较精细的日期类型 TIMESTAMP 描述 Data Type

133. 外键约束 FOREIGN KEY Constraint 部门表 员工表 外键 INSERT INTO 操作 允许 ( 部门表的主键列不存在数值 9) 允许 主键 … …

139. 创建其他对象 逻辑上显示一个或多个表的数据子集，不占用存储空间 View 产生单调递增的数值 Sequence 由数据行组成，基本的存储单元 Table 同义词，一个对象的替代名称 Synonym 增强查询性能 Index 描述 对象

141. 创建视图 CREATE [OR REPLACE] [FORCE| NOFORCE ] VIEW view [( alias [, alias ]...)] AS subquery [WITH CHECK OPTION [CONSTRAINT constraint ]] [WITH READ ONLY [CONSTRAINT constraint ]]; CREATE OR REPLACE VIEW empvu80 (id_number, name, sal, department_id) AS SELECT employee_id, first_name || ' ' || last_name, salary, department_id FROM employees WHERE department_id = 80;

149. 创建序列 CREATE SEQUENCE sequence [INCREMENT BY n ] [START WITH n ] [{MAXVALUE n | NOMAXVALUE }] [{MINVALUE n | NOMINVALUE }] [{CYCLE | NOCYCLE }] [{CACHE n | NOCACHE}];

161. 控制用户访问

162. 控制用户访问 DB 管理员 用户 用户名、密码 权限

165. 创建用户 CREATE USER demo IDENTIFIED BY demo; CREATE USER user IDENTIFIED BY password ;

167. 角色 Roles 不使用 roles 进行权限分配 使用 roles 进行权限分配 权限 用户 Manager

168. 创建角色 CREATE ROLE manager; GRANT create table, create view TO manager; GRANT manager TO BELL, KOCHHAR;

169. 对象权限 对象 权限 表 视图 序列 ALTER DELETE INDEX INSERT REFERENCES SELECT UPDATE