Tell me Anna Powierza's journal's themes.
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 = "Anna Powierza"
How about her sales?
select t3.sales 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 = "Anna Powierza"
What are the names of editors that are on the committee of journals with sales bigger than 3000?
select t2.name 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 t3.sales > 3000