A travel and tour company has two tables relating to customers and Fam

Question

A travel and tour company has two tables relating to customers and Families , Hacker Question , SQL

mysql - Compared two tables with no keys - Stack Overflow

Answer : 

SELECT MAX(tour_count.tours) FROM ( SELECT ( SELECT COUNT(*) AS num FROM COUNTRIES c WHERE c.MIN_SIZE <= a.FAMILY_SIZE ) AS tours FROM FAMILIES a ) AS tour_count