CDM Table name: OBSERVATION_PERIOD (CDM v5.3 / v5.4)

Reading from hesae_attendance.

Use the hesae_attendance table to populate the observation_period table.

Figure.1

Destination Field	Source field	Logic	Comment field
observation_period_id		nextval(‘public.observation_period_seq’) AS observation_period_id	Autogenerate
person_id	patid
observation_period_start_date	arrivaldate	Retrieve the earliest date among those dates like this: LEAST(MIN(arrivaldate),linkage_coverag.end) AS min_date
observation_period_end_date	arrivaldate	Retrieve the latest date among the date fields like this: GREATEST(MIN(arrivaldate), linkage_coverag.start) AS max_date
period_type_concept_id		32880