Multiple outer joins submitted via ODBC driver to MS Access??

I am using PHP 4.1 with the ODBC driver on MS Windows 2000, running IIS. I am trying to submit a SQL statement with multiple outer joins to a MS Access database. Does anyone know the syntax for creating such MULTIPLE outer joins? As it is, my current SQL statement drops rows for which certain columns have NULL values. Thanks, Bill. My current, inner join syntax is: $class_query = "SELECT sample.Sample, type.type_name, chon_class.class_name, chon_group.groupname, brecciation.brec_type FROM sample,type,chon_class,chon_group,brecciation WHERE sample.type = type.type AND sample.chon_class = chon_class.chon_class AND sample.chon_group = chon_group.chon_group AND sample.brecciation = brecciation.brecciation AND sample.type=$met_type AND chon_class.class_name LIKE '%$chondritic_class%' ORDER BY chon_group.groupname,brecciation.brec_type";