HOW TO
When data is joined in ArcMap using the default 'Keep all records' option some rows may have no data values. This occurs when a row in the destination table doesn't have a matching row in the source table.
tableB.fieldB is Null and FeatureClassA.OBJECTID is Not Null
Note:
Because the OBJECTID field does not allow Nulls, the 'FeatureClassA.OBJECTID is Not Null' part of the query will return True for all rows.
Article ID:000004693
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