API 5.20 supports sub-queries during any API query.

The syntax is:

• filter=attributeName(OPERATOR){ResourceName.attributeName[filter_1],[filter_2],[filter_n]}

en-capsuling sub-queries between {} and the filters inside the sub-queries as list inside [ ]

http://g2o-dev.dataloy.com/ws/rest/Cargo?filter=charterer.businessPartnerCode(IN)(133105,105882,123125,136200)&filter=key(IN)({Cargo.key[cargoPorts.portCall.eventLogs.event.eventCode(EQ)ARR][cargoPorts.portCall.eventLogs.eventLogDate(GT)2020-06-18T17:02:21][cargoPorts.cargoPortSequence(EQ)1],[cargoPorts.reasonForCall.reasonForCall(EQ)D]})&filter=key(IN)({Cargo.key[cargoPorts.portCall.eventLogs.event.eventCode(EQ)DEP][cargoPorts.portCall.eventLogs.eventLogDate(LT)2020-06-18T17:02:21][cargoPorts.cargoPortSequence(EQ)1],[cargoPorts.reasonForCall.reasonForCall(EQ)L]})

http://g2o-dev.dataloy.com/ws/rest/Cargo?filter=charterer.businessPartnerCode(IN)(133105,105882,123125,136200)&filter=key(IN)(%7BCargo.key[cargoPorts.portCall.eventLogs.event.eventCode(EQ)ARR][cargoPorts.portCall.eventLogs.eventLogDate(GT)2020-06-18T17:02:21][cargoPorts.cargoPortSequence(EQ)1],[cargoPorts.reasonForCall.reasonForCall(EQ)D]%7D)&filter=key(IN)(%7BCargo.key[cargoPorts.portCall.eventLogs.event.eventCode(EQ)DEP][cargoPorts.portCall.eventLogs.eventLogDate(LT)2020-06-18T17:02:21][cargoPorts.cargoPortSequence(EQ)1],[cargoPorts.reasonForCall.reasonForCall(EQ)L]%7D)

The character { must be encoded with %7B and } with %7D