如何在C#中查找数据表中特定列的重复项并返回重复项的行号作为输出

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;

public class Program
{
    public static void Main()
    {
        string connectionString = "YourConnectionString"; // 替换为实际的数据库连接字符串
        string tableName = "YourTableName"; // 替换为实际的数据表名称
        string columnName = "YourColumnName"; // 替换为实际的列名

        List<int> duplicateRows = FindDuplicateRows(connectionString, tableName, columnName);
        Console.WriteLine("Duplicate rows:");
        foreach (int rowNumber in duplicateRows)
        {
            Console.WriteLine(rowNumber);
        }
    }

    public static List<int> FindDuplicateRows(string connectionString, string tableName, string columnName)
    {
        List<int> duplicateRows = new List<int>();
        HashSet<string> uniqueValues = new HashSet<string>();

        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();

            string query = $"SELECT {columnName}, ROW_NUMBER() OVER (ORDER BY (SELECT 0)) AS RowNumber FROM {tableName}";
            using (SqlCommand command = new SqlCommand(query, connection))
            {
                using (SqlDataReader reader = command.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        string value = reader[columnName].ToString();
                        int rowNumber = Convert.ToInt32(reader["RowNumber"]);

                        if (uniqueValues.Contains(value))
                        {
                            duplicateRows.Add(rowNumber);
                        }
                        else
                        {
                            uniqueValues.Add(value);
                        }
                    }
                }
            }
        }

        return duplicateRows;
    }
}