CREATE TABLE club (clubid VARCHAR(255), clubname VARCHAR(255)); CREATE TABLE student (stuid VARCHAR(255), age VARCHAR(255)); CREATE TABLE member_of_club (clubid VARCHAR(255), stuid VARCHAR(255))
How many members of club "Bootup Baltimore" are younger than 18?
    
SQL: SELECT COUNT(*) FROM club AS t1 JOIN member_of_club AS t2 ON t1.clubid = t2.clubid JOIN student AS t3 ON t2.stuid = t3.stuid WHERE t1.clubname = "Bootup Baltimore" AND t3.age < 18