var connectionString = "server=localhost;database=mysqltest;userid=root;password=pass";
using var mscConnection = new MySqlConnector.MySqlConnection(connectionString);
mscConnection.Open();
using var msdConnection = new MySql.Data.MySqlClient.MySqlConnection(connectionString);
msdConnection.Open();
using (var mscCommand = mscConnection.CreateCommand())
{
	mscCommand.CommandText = """
		DROP TABLE IF EXISTS test3;
		DROP TABLE IF EXISTS test4;
		-- Here is the SQL to create the two tables
		-- Primary key
		CREATE TABLE test3 (colA VARCHAR(25), colB VARCHAR(25), colC VARCHAR(25), colD VARCHAR(25), PRIMARY KEY (colA, colB, colC));

		INSERT INTO test3 (colA, colB, colC, colD) VALUES ('A', 'A', 'A', 'A');
		INSERT INTO test3 (colA, colB, colC, colD) VALUES ('A', 'B', 'A', 'A');
		INSERT INTO test3 (colA, colB, colC, colD) VALUES ('B', 'A', 'A', 'A');
		INSERT INTO test3 (colA, colB, colC, colD) VALUES ('C', 'A', 'A', 'A');

		-- No primary Key
		CREATE TABLE test4 (colA VARCHAR(25), colB VARCHAR(25), colC VARCHAR(25), colD VARCHAR(25));

		INSERT INTO test4 (colA, colB, colC, colD) VALUES ('A', 'A', 'A', 'A');
		INSERT INTO test4 (colA, colB, colC, colD) VALUES ('A', 'B', 'A', 'A');
		INSERT INTO test4 (colA, colB, colC, colD) VALUES ('B', 'A', 'A', 'A');
		INSERT INTO test4 (colA, colB, colC, colD) VALUES ('C', 'A', 'A', 'A');
		""";
	mscCommand.ExecuteNonQuery();
}
foreach (var connection in new DbConnection[] { mscConnection, msdConnection })
{
	foreach (var sql in new[] { "SELECT colA FROM test3", "SELECT colA FROM test4" })
	{
		using var command = connection.CreateCommand();
		command.CommandText = sql;
		Console.WriteLine("{0} --- {1}", command.CommandText, command.GetType().FullName);
		using var reader = command.ExecuteReader();
		{
			while (reader.Read())
			{
				Console.WriteLine(reader.GetValue(0));
			}
		}
		Console.WriteLine();
	}
}

SELECT colA FROM test3 --- MySqlConnector.MySqlCommand
A
A
B
C
SELECT colA FROM test4 --- MySqlConnector.MySqlCommand
A
A
B
C
SELECT colA FROM test3 --- MySql.Data.MySqlClient.MySqlCommand
A
A
B
C
SELECT colA FROM test4 --- MySql.Data.MySqlClient.MySqlCommand
A
A
B
C

		using var da = command is MySqlConnector.MySqlCommand ?
			(DbDataAdapter) new MySqlConnector.MySqlDataAdapter((MySqlConnector.MySqlCommand) command) :
			new MySql.Data.MySqlClient.MySqlDataAdapter((MySql.Data.MySqlClient.MySqlCommand) command);
		Console.WriteLine("{0} --- {1}", command.CommandText, da.GetType().FullName);
		var ds = new DataSet();
		da.ReturnProviderSpecificTypes = true;
		da.Fill(ds);
		foreach (DataRow row in ds.Tables[0].Rows)
			Console.WriteLine(row[0]);
		Console.WriteLine();

SELECT colA FROM test3 --- MySqlConnector.MySqlDataAdapter
A
A
B
C
SELECT colA FROM test4 --- MySqlConnector.MySqlDataAdapter
A
A
B
C
SELECT colA FROM test3 --- MySql.Data.MySqlClient.MySqlDataAdapter
A
A
B
C
SELECT colA FROM test4 --- MySql.Data.MySqlClient.MySqlDataAdapter
A
A
B
C