server_db_row_t server_db_fetch_row(server_db_result_t *result)
Returns a row from the result, NULL is returned when either there was an error or no row.
The result you provide is obtained with server_db_query()
You interact with this row type just like with libmysqlclient, so if you are confused you might want to look at the libmysqlclient documentation.
See the general example included at the bottom of this section for a model usage.