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模糊查询Oracle中两表数据的实现方法
在实际开发中，需要对数据库中的数据进行模糊查询。而在Oracle中，通过使用LIKE关键字实现模糊查询。本文将介绍如何使用LIKE关键字在两个表中进行模糊查询。
1.创建两个表
我们需要创建两个表来演示模糊查询的实现方法。下面是创建表的SQL语句：
CREATE TABLE employees (
employee_id NUMBER,
first_name VARCHAR2(50),
last_name VARCHAR2(50),
eml VARCHAR2(50),
phone_number VARCHAR2(20),
hire_date DATE,
job_id VARCHAR2(30),
salary NUMBER,
commission_pct NUMBER,
manager_id NUMBER,
department_id NUMBER
);
CREATE TABLE departments (
department_id NUMBER,
department_name VARCHAR2(50),
manager_id NUMBER,
location_id NUMBER
);
2.插入数据
接下来，我们需要向两个表中插入一些数据。下面是插入数据的SQL语句：
INSERT INTO employees VALUES(100, ‘Steven’, ‘King’, ‘steven.king@oracle.com’, ‘123.456.7890’, TO_DATE(‘2003-06-17’, ‘YYYY-MM-DD’), ‘AD_PRES’, 24000, NULL, NULL, 90);
INSERT INTO employees VALUES(101, ‘Neena’, ‘Kochhar’, ‘neena.kochhar@oracle.com’, ‘123.456.7899’, TO_DATE(‘2005-09-21’, ‘YYYY-MM-DD’), ‘AD_VP’, 17000, NULL, 100, 90);
INSERT INTO employees VALUES(102, ‘Lex’, ‘De Haan’, ‘lex.dehaan@oracle.com’, ‘123.456.7898’, TO_DATE(‘2001-01-13’, ‘YYYY-MM-DD’), ‘AD_VP’, 17000, NULL, 100, 90);
INSERT INTO employees VALUES(103, ‘Alexander’, ‘Hunold’, ‘alexander.hunold@oracle.com’, ‘123.456.7897’, TO_DATE(‘2006-01-03’, ‘YYYY-MM-DD’), ‘IT_PROG’, 9000, NULL, 102, 60);
INSERT INTO employees VALUES(104, ‘Bruce’, ‘Ernst’, ‘bruce.ernst@oracle.com’, ‘123.456.7896’, TO_DATE(‘2007-05-21’, ‘YYYY-MM-DD’), ‘IT_PROG’, 6000, NULL, 103, 60);
INSERT INTO departments VALUES(10, ‘Administration’, 200, 1700);
INSERT INTO departments VALUES(20, ‘Marketing’, 201, 1800);
INSERT INTO departments VALUES(30, ‘Purchasing’, 114, 1700);
INSERT INTO departments VALUES(40, ‘Human Resources’, 203, 2400);
INSERT INTO departments VALUES(50, ‘Shipping’, 121, 1500);
3.利用LIKE关键字实现模糊查询
在Oracle中，可以使用LIKE关键字实现模糊查询。当我们想在两个表中查询包含特定字符串的记录时，可以使用以下SQL语句：
SELECT *
FROM employees e, departments d
WHERE e.department_id = d.department_id AND (e.first_name LIKE ‘%Alex%’ OR e.last_name LIKE ‘%Alex%’ OR d.department_name LIKE ‘%Adminis%’);
以上SQL语句将返回包含Alex或Administr的员工和部门记录。其中，%表示匹配任意字符，包括空字符。
4.完整实现代码
我们将以上三个步骤整合成一段完整的实现代码：
CREATE TABLE employees (
employee_id NUMBER,
first_name VARCHAR2(50),
last_name VARCHAR2(50),
eml VARCHAR2(50),
phone_number VARCHAR2(20),
hire_date DATE,
job_id VARCHAR2(30),
salary NUMBER,
commission_pct NUMBER,
manager_id NUMBER,
department_id NUMBER
);
CREATE TABLE departments (
department_id NUMBER,
department_name VARCHAR2(50),
manager_id NUMBER,
location_id NUMBER
);
INSERT INTO employees VALUES(100, ‘Steven’, ‘King’, ‘steven.king@oracle.com’, ‘123.456.7890’, TO_DATE(‘2003-06-17’, ‘YYYY-MM-DD’), ‘AD_PRES’, 24000, NULL, NULL, 90);
INSERT INTO employees VALUES(101, ‘Neena’, ‘Kochhar’, ‘neena.kochhar@oracle.com’, ‘123.456.7899’, TO_DATE(‘2005-09-21’, ‘YYYY-MM-DD’), ‘AD_VP’, 17000, NULL, 100, 90);
INSERT INTO employees VALUES(102, ‘Lex’, ‘De Haan’, ‘lex.dehaan@oracle.com’, ‘123.456.7898’, TO_DATE(‘2001-01-13’, ‘YYYY-MM-DD’), ‘AD_VP’, 17000, NULL, 100, 90);
INSERT INTO employees VALUES(103, ‘Alexander’, ‘Hunold’, ‘alexander.hunold@oracle.com’, ‘123.456.7897’, TO_DATE(‘2006-01-03’, ‘YYYY-MM-DD’), ‘IT_PROG’, 9000, NULL, 102, 60);
INSERT INTO employees VALUES(104, ‘Bruce’, ‘Ernst’, ‘bruce.ernst@oracle.com’, ‘123.456.7896’, TO_DATE(‘2007-05-21’, ‘YYYY-MM-DD’), ‘IT_PROG’, 6000, NULL, 103, 60);
INSERT INTO departments VALUES(10, ‘Administration’, 200, 1700);
INSERT INTO departments VALUES(20, ‘Marketing’, 201, 1800);
INSERT INTO departments VALUES(30, ‘Purchasing’, 114, 1700);
INSERT INTO departments VALUES(40, ‘Human Resources’, 203, 2400);
INSERT INTO departments VALUES(50, ‘Shipping’, 121, 1500);
SELECT *
FROM employees e, departments d
WHERE e.department_id = d.department_id AND (e.first_name LIKE ‘%Alex%’ OR e.last_name LIKE ‘%Alex%’ OR d.department_name LIKE ‘%Adminis%’);
通过以上代码，我们可以轻松地实现模糊查询Oracle中两个表的数据。在实际工作中，可以通过类似的方式实现更为复杂的查询需求。
