Sqlserver query: when a.id is the same as b.id, and the A.P corresponding to a.id cannot be found in the B.P corresponding to b.id, the a.id and A.P will be displayed

Want to query as shown , How to write sentences :
Premise : a.id Some value ,b.id Have a basic , but a.id The value of is not repeated .
Purpose : a.id = b.id Under the circumstances , a.id Corresponding a.p stay b.id Corresponding b.p If you can't find it in , It shows this a.id and a.p