CREATE TABLE editor (Editor_ID NUMBER, Name CLOB, Age FLOAT)
CREATE TABLE journal (Journal_ID NUMBER, Date CLOB, Theme CLOB, Sales NUMBER)
CREATE TABLE journal_committee (Editor_ID NUMBER, Journal_ID NUMBER, Work_Type CLOB)

Just compare the number of journal committees of each editor using a histogram.
SELECT Name, COUNT(*) FROM editor AS T1 JOIN journal_committee AS T2 ON T1.Editor_ID = T2.Editor_ID GROUP BY T1.Editor_ID
SELECT "Name", COUNT(*) FROM "editor" "T1" JOIN "journal_committee" "T2" ON "T1"."Editor_ID" = "T2"."Editor_ID" GROUP BY "T1"."Editor_ID"