Standalone Table — Select where no duplicates, join to FC, update table's field with joined shape length

[Bud]

ArcGIS Pro 2.9.5; Oracle 18c 10.7.1 EGDB

I have a ROADS line FC (has an ID field) and an EVENTS standalone table. EVENTS is a linear referencing table with ID, FMEAS (double), and TMEAS (double) fields. The relationship between ROADS and EVENTS is 1:M. One road to 0, 1, or more events.

Some of the EVENTS.TMEAS values are larger than the length of the related road, which is incorrect.

I want to:

1. Select EVENTS where there is only one event per road.
2. Join EVENTS to ROADS to bring the ROAD shape length field into the EVENTS attribute table.
3. Calculate field: For the selected EVENTS, update the FMEAS field to the ROAD's shape length.

How can I do that?

I am running into join errors when trying to use a SQL subquery for the selection, so am looking for a different approach.

[DuncanHornby]

My gut feeling is you need to create your route events using your linear referencing then export those into a polyline FeatureClass and do your spatial querying. Then as some final processing step copy your fields of interest back into the original standalone event tables.