PostgresException：'42601：syntax error at or near“$1”位置：25

public async Task Delete(string dbName) { 
    using(var connection = GetNewConnection()) { 
    connection.Open();
        using(var command = new NpgsqlCommand("DROP DATABASE IF EXISTS @dbName;", connection)) {
            command.Parameters.AddWithValue("@dbName", dbName);
            command.ExecuteNonQuery();
        } 
    }
    await Task.CompletedTask;
}

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