UPDATE TeacherSite set OwnerSiteId=
	(SELECT
		ST.WebSiteId
 	 FROM
		SchoolSite_Teachers ST
	 WHERE
		ST.HybridUserId = TeacherSite.HybridUserId
	)

update ts
set ts.ownersiteid = ts2.websiteid
from Teachersite ts
join schoolsite_teachers ts2 on st.hybriduserid = ts.hybriduserid