CDM Table name: observation_period

Reading from tumour, treatment, linkage_coverage

Destination Field	Source field	Logic	Comment field
observation_period_id			Autogenerate
person_id	e_patid
observation_period_start_date	diagnosisdatebest eventdate start	GREATEST(LEAST(MIN(diagnosisdatebest), MIN(eventdate)), start)
observation_period_end_date	diagnosisdatebest eventdate end	LEAST(GREATEST(MAX(diagnosisdatebest), MAX(eventdate)), end)
period_type_concept_id		32880 - Standard algorithm