tell me the number of journal committees of editor Kamila Porczyk.
select count(*) from editor as t1 join journal_committee as t2 on t1.editor_id = t2.editor_id where t1.name = "Kamila Porczyk"
Okay, I want to know the themes of his journals.
select t3.theme from journal_committee as t1 join editor as t2 on t1.editor_id = t2.editor_id join journal as t3 on t1.journal_id = t3.journal_id where t2.name = "Szymon Wydra"
Tell me the names of editors that are not on any journal committee.
select name from editor where editor_id not in (select editor_id from journal_committee)