10 2012 档案

mysql利用子查询后的效率影响
摘要：仅仅是利用id:explain SELECT * from customer where id in(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20)结果：利用了子查询：explain SELECT id,`name` FROM customer where id IN(select DISTINCT(customerid) from searchaccount WHERE kfuid=126 AND iskf=1) LIMIT 20结果：不用子查询，达到同样的效果：explain select DISTINCT(customerid) a 阅读全文
posted @ 2012-10-12 14:46 编程思想家 阅读(1017) 评论(0) 推荐(0) 编辑