ALTER TABLE table_name ADD COLUMN column_name column_type;

ALTER TABLE users ADD COLUMN last_login TIMESTAMP;

-- 1. 创建新表结构
CREATE TABLE users_new (
    id INTEGER PRIMARY KEY,
    username TEXT NOT NULL,
    email TEXT UNIQUE,
    last_login TIMESTAMP,  -- 新增字段
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- 2. 从旧表复制数据
INSERT INTO users_new (id, username, email, created_at)
SELECT id, username, email, created_at FROM users;

-- 3. 删除旧表
DROP TABLE users;

-- 4. 重命名新表
ALTER TABLE users_new RENAME TO users;

import sqlite3

def add_column(database_path, table_name, column_name, column_type):
    conn = sqlite3.connect(database_path)
    cursor = conn.cursor()
    
    try:
        cursor.execute(f"ALTER TABLE {table_name} ADD COLUMN {column_name} {column_type}")
        conn.commit()
        print(f"成功添加字段 {column_name} 到表 {table_name}")
    except sqlite3.Error as e:
        print(f"添加字段失败: {e}")
    finally:
        conn.close()

# 使用示例
add_column('my_database.db', 'users', 'phone_number', 'TEXT')

import java.sql.*;

public class SQLiteAddColumn {
    public static void addColumn(String dbPath, String table, String column, String type) {
        String url = "jdbc:sqlite:" + dbPath;
        
        try (Connection conn = DriverManager.getConnection(url);
             Statement stmt = conn.createStatement()) {
            
            String sql = String.format("ALTER TABLE %s ADD COLUMN %s %s", 
                                      table, column, type);
            stmt.execute(sql);
            System.out.println("字段添加成功");
            
        } catch (SQLException e) {
            System.out.println("添加字段时出错: " + e.getMessage());
        }
    }
}