Setting up row level security with lookupvalue

[Anonymous]

Hi all, I'm relatively new to DAX expressions and my head is spinning a little bit so hopefully I can get some clarity here.

Say I have two tables:

Table_1

Grade	Year	Month	SchoolID
			11111
			33333
			22222
			44444

Table_2

Email	IdentityID	SchoolID
test@gmail.com	10	11111
test@hotmail.com	10	22222

My report consists only of data in table_1. When logging in to access the report, a user may log in with their gmail or hotmail account and will access the same data, rows from Table_1 where SchoolID IN (11111,22222).

In Power BI, I'm trying to create a DAX expression that will get the identity ID from the UserPrincipalName, get all SchoolIDs that match that IdentityIDs, and show all rows from Table_1 that have SchoolID in that list of SchoolIDs. 

I tried playing around with LOOKUPVALUE but since that only returns a single value, I'm not sure if that's the right track.

[lbendlin]

You can use TREATAS to bridge the air gap between tables if they have equivalent sets of columns.