查询优化

Question

有什么方法可以更快地优化此查询？

SELECT id FROM business 
WHERE id NOT IN(SELECT business_id FROM business_community GROUP BY business_id) 

Answer 1

试试这个：

SELECT id FROM business AS b 
LEFT JOIN business_community bc ON bc.business_id = b.id 
WHERE bc.business_id IS NULL 

Answer 2

也许用 “DISTINCT business_id”，而不是一组由..