adb shell content query --uri content://telephony/carriers/preferapn

adb shell content query --uri content://telephony/carriers/ --where "numeric='50502'"

Row: 5 _id=2912, name=Optus MMS, numeric=50502, mcc=505, mnc=02, apn=mms, user=*,
server=*, password=*, proxy=202.139.83.152, port=8070, mmsproxy=61.88.190.10, mmsport=8070,
mmsc=http://mmsc.optus.com.au:8002/, authtype=-1, type=mms, current=1, protocol=IP,
roaming_protocol=IP, carrier_enabled=1, bearer=0, bearer_bitmask=0, mvno_type=,
mvno_match_data=, sub_id=3, profile_id=0, modem_cognitive=0, max_conns=0, wait_time=0,
max_conns_time=0, mtu=0, edited=0, user_visible=1, user_editable=1

adb shell content insert --uri content://telephony/carriers/preferapn/subId/2 --bind apn_id:l:2912