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

Reading from hes_hospital,hes_episodes.

Use the hes_hospital & hes_episodes tables 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	admidate,hes_episodes.epistart	Retrieve the earliest date among those dates like this: LEAST(MIN(admidate), MIN(hes_episodes.epistart)) AS min_date
observation_period_end_date	discharged,hes_episodes.epiend	Retrieve the latest date among the date fields like this: GREATEST(MAX(discharged), MAX(hes_episodes.epiend)) AS max_date
period_type_concept_id		32880