Table schema:
CREATE TABLE participants (Participant_ID VARCHAR, participant_details VARCHAR); CREATE TABLE Participants_in_Events (Participant_ID VARCHAR)

Question: How many events had participants whose details had the substring 'Dr.'
SQL: SELECT COUNT(*) FROM participants AS T1 JOIN Participants_in_Events AS T2 ON T1.Participant_ID = T2.Participant_ID WHERE T1.participant_details LIKE '%Dr.%'