oracle数据库sql语句示例

Oracle数据库SQL语句是用于管理和操作数据的基础。以下是几个常见的SQL语句示例：

1. **创建表（CREATE TABLE）**:

   CREATE TABLE Employees (
       EmployeeID NUMBER(4) PRIMARY KEY,
       FirstName VARCHAR2(20),
       LastName VARCHAR2(20),
       HireDate DATE
   );

2. **插入记录（INSERT INTO）**:

   INSERT INTO Employees (EmployeeID, FirstName, LastName, HireDate)
   VALUES (101, 'John', 'Doe', TO_DATE('2020-01-01', 'YYYY-MM-DD'));

3. **查询数据（SELECT）**:

   SELECT * FROM Employees WHERE EmployeeID = 101;

或者

   SELECT FirstName, LastName FROM Employees;

4. **更新记录（UPDATE）**:

   UPDATE Employees SET LastName = 'Smith' WHERE EmployeeID = 101;

5. **删除记录（DELETE）**:

   DELETE FROM Employees WHERE EmployeeID = 101;

6. **连接两个表（JOIN）**:

   SELECT e.FirstName, e.LastName, d.DepartmentName
   FROM Employees e
   JOIN Departments d ON e.DepartmentID = d.DepartmentID;