Query time 1回目 2,000,000 SELECT * FROM customers WHERE Country = ‘Japan’; 331.3ms 2回目 2,000,000 SELECT * FROM customers WHERE Country = ‘Japan’; 334.7ms 3回目 2,000,000 SELECT * FROM customers WHERE Country = ‘Japan’; 288.7ms 4回目 2,000,000 SELECT * FROM customers WHERE Country = ‘Japan’; 288.7ms 5回目 2,000,000 SELECT * FROM customers WHERE Country = ‘Japan’; 284.7ms 28