What percentage of legendary frame effect cards have a maximum starting maximun hand
size of +3?
maximun hand size of +3 refer to hand = +3; legendary frame effect cards refer to frameEffects = 'legendary'; percentage refer to DIVIDE(COUNT(hand = '+3'), COUNT(id)) from cards where frameEffects = 'legendary'
SELECT SUM(CASE WHEN hAND = '+3' THEN 1.0 ELSE 0 END) / COUNT(id) * 100 FROM cards WHERE frameEffects = 'legendary'