unity 查询mysql数据库中某个表的所有数据，之后找出相同的数据

以下是Unity中使用C#查询MySQL数据库中某个表的所有数据，并找出相同数据的示例代码：

using System.Collections.Generic;
using MySql.Data.MySqlClient;

public class MySQLManager {

    private MySqlConnection connection;
    private string server;
    private string database;
    private string uid;
    private string password;

    public MySQLManager() {
        server = "localhost";
        database = "mydatabase";
        uid = "root";
        password = "password";
        string connectionString = "SERVER=" + server + ";" + "DATABASE=" + 
            database + ";" + "UID=" + uid + ";" + "PASSWORD=" + password + ";";
        connection = new MySqlConnection(connectionString);
    }

    public List<string> QueryDataFromTable(string tableName) {
        List<string> dataList = new List<string>();
        string query = "SELECT * FROM " + tableName;
        MySqlCommand cmd = new MySqlCommand(query, connection);
        
        try {
            connection.Open();
            MySqlDataReader dataReader = cmd.ExecuteReader();
            while (dataReader.Read()) {
                string data = "";
                for (int i = 0; i < dataReader.FieldCount; i++) {
                    data += dataReader[i].ToString() + ",";
                }
                if (!string.IsNullOrEmpty(data)) {
                    dataList.Add(data);
                }
            }
            dataReader.Close();
        } catch (MySqlException ex) {
            Debug.LogError("MySQL Error: " + ex.Message);
        } finally {
            connection.Close();
        }

        return dataList;
    }

    public List<string> FindDuplicateData(List<string> dataList) {
        List<string> duplicateList = new List<string>();
        HashSet<string> hashSet = new HashSet<string>();
        foreach (string data in dataList) {
            if (!hashSet.Add(data)) {
                duplicateList.Add(data);
            }
        }
        return duplicateList;
    }
}

使用方法：

MySQLManager mySQLManager = new MySQLManager();
List<string> dataList = mySQLManager.QueryDataFromTable("mytable");
List<string> duplicateList = mySQLManager.FindDuplicateData(dataList);
foreach (string data in duplicateList) {
    Debug.Log(data);
}

在上面的示例代码中，需要根据实际情况修改MySQL数据库连接的相关信息。QueryDataFromTable方法用于查询指定表中的所有数据，并将其放入List<string>中返回。FindDuplicateData方法用于找出相同的数据，并将其放入List<string>中返回。这里使用HashSet来判断是否存在重复数据。最后，使用上述方法可以查询指定表中的所有数据，并找出相同的数据。