ArcGIS Pro 2.6.8; Oracle 18c 10.7.1 EGDB:
Is the join one-to-first?
In other words, for each input table row, does the value from the first arbitrary match in the join table get used in the new fields in the input table?
Or am I misunderstanding how that tool works?
Accepted Solutions
In the newest version of Join Field, the Transfer Method has been exposed.
So the help topic helps to clarify what happens if you select a field rather than use Field Mapping
If the Select transfer fields option is specified for the Transfer Method parameter and field values in the Join Table Field parameter value are not unique, only the first occurrence of each value will be used. To account for values other than the first occurrence (a one-to-many join), set the Transfer Method parameter to Use field mapping. To perform a one-to-many join, the Input Table parameter value must have an Object ID field and be in the same workspace as the Join Table parameter value.
In the newest version of Join Field, the Transfer Method has been exposed.
So the help topic helps to clarify what happens if you select a field rather than use Field Mapping
If the Select transfer fields option is specified for the Transfer Method parameter and field values in the Join Table Field parameter value are not unique, only the first occurrence of each value will be used. To account for values other than the first occurrence (a one-to-many join), set the Transfer Method parameter to Use field mapping. To perform a one-to-many join, the Input Table parameter value must have an Object ID field and be in the same workspace as the Join Table parameter value.
