Im working on a dotnet project wherein the task is to compare 2 tables which are copy of each other, table1[old] and table1_copy[new] as of now im using a ‘for loop’ and comparing the 2 tables based on primary key row by row.

*The above approach is quite slow as there are nearly 13lakhs rows in a table.
So suggest a fast approach to do the same.
*
Below is my used approach.

static void CompareTables(string connectionString, string tableName1, string tableName2, string primaryKeyColumn)
    {
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            try
            {
                connection.Open();
                Console.WriteLine();

                Console.WriteLine("Connection Opened!");
                // Load data from both tables into a DataSet
                DataSet ds = new DataSet();
                Console.WriteLine($"Comparing {tableName1} and {tableName2}");

                SqlDataAdapter adapter1 = new SqlDataAdapter($"SELECT * FROM {tableName1}", connection);
                adapter1.Fill(ds, tableName1);

                SqlDataAdapter adapter2 = new SqlDataAdapter($"SELECT * FROM {tableName2}", connection);
                adapter2.Fill(ds, tableName2);

                DataTable dtOriginal = ds.Tables[tableName1];
                DataTable dtCopy = ds.Tables[tableName2];

                // Create a dictionary to store the original table data for quick lookup
                // Dictionary<object, DataRow> originalTableDict = new Dictionary<object, DataRow>();
                // foreach (DataRow row in dtOriginal.Rows)
                // {
                //     originalTableDict[row[primaryKeyColumn]] = row;
                // }

                bool changesFound = false;

                 foreach (DataRow rowCopy in dtCopy.Rows)
                {
                    DataRow[] originalRows = dtOriginal.Select($"{primaryKeyColumn} = {rowCopy[primaryKeyColumn]}");
                    if (originalRows.Length > 0)
                    {
                        DataRow rowOriginal = originalRows[0];
                        for (int i = 0; i < dtOriginal.Columns.Count; i++)
                        {
                            string columnName = dtOriginal.Columns[i].ColumnName;
                            object originalValue = rowOriginal[columnName];
                            object copyValue = rowCopy[columnName];

                            if (!Equals(originalValue, copyValue))
                            {
                                if (!changesFound)
                                {
                                    changesFound = true;
                                    Console.WriteLine("Changes found:");
                                }

                                Console.WriteLine($"Row ID: {rowOriginal[primaryKeyColumn]}, Column: {columnName}, Original: {originalValue}, Updated: {copyValue}");
                            }
                        }
                    }
                }