Oracle 常用 SQL 命令集合

以下是一份全面的 Oracle 数据库常用 SQL 命令集合，涵盖数据库管理、对象操作、数据查询优化等核心功能：

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一、数据库连接与基本信息

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-- 连接到数据库
CONNECT username/password@service_name-- 查看当前用户
SHOW USER-- 查看数据库版本
SELECT * FROM v$version;-- 查看实例状态
SELECT instance_name, status, database_status FROM v$instance;

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二、表空间管理

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-- 查看表空间
SELECT tablespace_name, status, contents FROM dba_tablespaces;-- 创建表空间
CREATE TABLESPACE my_ts 
DATAFILE '/u01/oradata/mydb/my_ts01.dbf' SIZE 100M
AUTOEXTEND ON NEXT 10M MAXSIZE UNLIMITED;-- 扩展表空间
ALTER TABLESPACE my_ts ADD DATAFILE 
'/u01/oradata/mydb/my_ts02.dbf' SIZE 50M;-- 修改用户默认表空间
ALTER USER scott DEFAULT TABLESPACE my_ts;

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三、用户与权限

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-- 创建用户
CREATE USER dev_user IDENTIFIED BY "Str0ngP@ss"
DEFAULT TABLESPACE users
QUOTA UNLIMITED ON users;-- 授予权限
GRANT CREATE SESSION, CREATE TABLE TO dev_user;
GRANT SELECT, INSERT ON hr.employees TO dev_user;-- 创建角色
CREATE ROLE data_analyst;
GRANT SELECT ANY TABLE, CREATE VIEW TO data_analyst;-- 查看用户权限
SELECT * FROM dba_sys_privs WHERE grantee = 'DEV_USER';

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四、表管理

1. 创建表

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CREATE TABLE employees (emp_id NUMBER GENERATED ALWAYS AS IDENTITY PRIMARY KEY,first_name VARCHAR2(50) NOT NULL,last_name VARCHAR2(50),hire_date DATE DEFAULT SYSDATE,salary NUMBER(10,2),dept_id NUMBER,CONSTRAINT fk_dept FOREIGN KEY (dept_id) REFERENCES departments(dept_id)
) TABLESPACE users;

2. 修改表结构

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-- 添加列
ALTER TABLE employees ADD (phone VARCHAR2(15));-- 修改列
ALTER TABLE employees MODIFY (salary NUMBER(12,2));-- 重命名列
ALTER TABLE employees RENAME COLUMN phone TO mobile;-- 删除列
ALTER TABLE employees DROP COLUMN mobile;

3. 表维护

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-- 重命名表
RENAME employees TO staff;-- 截断表
TRUNCATE TABLE temp_data;-- 删除表
DROP TABLE employees PURGE;  -- 彻底删除

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五、数据操作 (CRUD)

1. 插入数据

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-- 插入单行
INSERT INTO employees (first_name, last_name, salary)
VALUES ('John', 'Doe', 5000);-- 插入多行
INSERT ALLINTO employees (first_name, last_name) VALUES ('Alice', 'Smith')INTO employees (first_name, last_name) VALUES ('Bob', 'Johnson')
SELECT 1 FROM dual;-- 从查询插入
INSERT INTO managers
SELECT * FROM employees WHERE salary > 8000;

2. 查询数据

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-- 分页查询 (12c+)
SELECT * FROM employees 
OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY;-- 正则表达式查询
SELECT * FROM employees 
WHERE REGEXP_LIKE(first_name, '^Ste(v|ph)en$');-- 层次查询
SELECT LPAD(' ', 2*(LEVEL-1)) || last_name AS org_chart
FROM employees
START WITH manager_id IS NULL
CONNECT BY PRIOR emp_id = manager_id;-- 分析函数
SELECT dept_id, AVG(salary) AS avg_sal,RANK() OVER (ORDER BY AVG(salary) DESC) dept_rank
FROM employees
GROUP BY dept_id;

3. 更新数据

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-- 关联更新
UPDATE employees e
SET salary = salary * 1.1
WHERE EXISTS (SELECT 1 FROM departments d WHERE d.dept_id = e.dept_id AND d.location = 'NEW YORK'
);-- 使用MERGE更新或插入
MERGE INTO bonuses b
USING (SELECT emp_id, salary, dept_id FROM employees WHERE hire_date > DATE '2020-01-01'
) e
ON (b.emp_id = e.emp_id)
WHEN MATCHED THEN UPDATE SET b.bonus = e.salary * 0.1
WHEN NOT MATCHED THEN INSERT (b.emp_id, b.bonus)
VALUES (e.emp_id, e.salary * 0.15);

4. 删除数据

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-- 关联删除
DELETE FROM employees e
WHERE dept_id IN (SELECT dept_id FROM departments WHERE location = 'CLOSED'
);

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六、索引管理

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-- 创建B-tree索引
CREATE INDEX idx_emp_name ON employees(last_name);-- 创建位图索引
CREATE BITMAP INDEX idx_emp_dept ON employees(dept_id);-- 创建函数索引
CREATE INDEX idx_emp_upper ON employees(UPPER(first_name));-- 重建索引
ALTER INDEX idx_emp_name REBUILD ONLINE;-- 监控索引使用
SELECT * FROM v$object_usage WHERE index_name = 'IDX_EMP_NAME';

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七、PL/SQL 基础

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-- 匿名块
DECLAREv_count NUMBER;
BEGINSELECT COUNT(*) INTO v_count FROM employees;DBMS_OUTPUT.PUT_LINE('Total employees: ' || v_count);-- 异常处理EXCEPTIONWHEN NO_DATA_FOUND THENDBMS_OUTPUT.PUT_LINE('No data found');
END;
/-- 创建存储过程
CREATE OR REPLACE PROCEDURE increase_salary (p_dept_id IN NUMBER, p_percent IN NUMBER
) AS
BEGINUPDATE employees SET salary = salary * (1 + p_percent/100)WHERE dept_id = p_dept_id;COMMIT;
END increase_salary;
/

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八、性能优化

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-- 执行计划分析
EXPLAIN PLAN FOR
SELECT * FROM employees WHERE dept_id = 10;
SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY);-- 收集统计信息
EXEC DBMS_STATS.GATHER_TABLE_STATS('HR', 'EMPLOYEES');-- SQL调优顾问
DECLAREtune_task VARCHAR2(30);
BEGINtune_task := DBMS_SQLTUNE.CREATE_TUNING_TASK(sql_text => 'SELECT * FROM employees WHERE salary > :1',bind_list => sql_binds(anydata.ConvertNumber(5000)),user_name => 'HR',scope => 'COMPREHENSIVE',time_limit => 60);DBMS_SQLTUNE.EXECUTE_TUNING_TASK(tune_task);
END;
/

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九、系统管理

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-- 查看锁信息
SELECT * FROM v$locked_object;-- 查看会话
SELECT sid, serial#, username, status FROM v$session;-- 终止会话
ALTER SYSTEM KILL SESSION '123,4567';  -- sid, serial#-- 表空间使用情况
SELECT tablespace_name, ROUND(SUM(bytes) / 1024/1024) total_mb,ROUND(SUM(bytes - NVL(free_bytes,0)) / 1024/1024) used_mb
FROM dba_data_files 
LEFT JOIN (SELECT tablespace_name ts, SUM(bytes) free_bytes FROM dba_free_space GROUP BY tablespace_name) 
USING (tablespace_name)
GROUP BY tablespace_name;

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十、数据字典视图

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-- 查看表结构
DESC user_tab_columns;
SELECT column_name, data_type, nullable 
FROM user_tab_columns 
WHERE table_name = 'EMPLOYEES';-- 查看约束
SELECT constraint_name, constraint_type 
FROM user_constraints 
WHERE table_name = 'EMPLOYEES';-- 查看索引
SELECT index_name, column_name 
FROM user_ind_columns 
WHERE table_name = 'EMPLOYEES';-- 查看对象依赖
SELECT * FROM user_dependencies 
WHERE referenced_name = 'EMPLOYEES';

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十一、备份与恢复

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-- 数据泵导出 (命令行)
expdp system/password DIRECTORY=data_pump_dir DUMPFILE=hr.dmp SCHEMAS=hr-- 数据泵导入
impdp system/password DIRECTORY=data_pump_dir DUMPFILE=hr.dmp REMAP_SCHEMA=hr:new_hr-- RMAN备份 (命令行)
rman TARGET /
BACKUP DATABASE PLUS ARCHIVELOG;

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Oracle 特色功能提醒：

1. 高级分区：支持范围、列表、哈希、复合分区

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   CREATE TABLE sales (sale_id NUMBER,sale_date DATE,amount NUMBER
   ) PARTITION BY RANGE (sale_date) (PARTITION p2022 VALUES LESS THAN (DATE '2023-01-01'),PARTITION p2023 VALUES LESS THAN (MAXVALUE)
   );
   

2. 虚拟列：

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   ALTER TABLE employees ADD (name_caps VARCHAR2(100) GENERATED ALWAYS AS (UPPER(first_name || ' ' || last_name)));
   

3. 闪回技术：

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   -- 查询历史数据
   SELECT * FROM employees AS OF TIMESTAMP SYSTIMESTAMP - INTERVAL '1' HOUR;-- 恢复被删除的表
   FLASHBACK TABLE employees TO BEFORE DROP;
   

4. 结果缓存：

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   SELECT /*+ RESULT_CACHE */ AVG(salary) FROM employees;
   

重要提示：

1. Oracle 区分大小写（除非使用双引号）
2. 使用 COMMIT 提交事务，ROLLBACK 回滚
3. 生产环境操作前建议使用 SAVEPOINT
4. 使用 SQL*Plus 时，以分号 ; 或 / 结束语句
5. 注意 Oracle 中的空值处理（NULL 参与运算结果通常为 NULL）