mysql查询语法

1、查询某天的数据量: SELECT count(*) from crawled_goods where channel='yijiupi-beijing' and datediff(created_at,NOW()) = -1(0代表今天，-1代表昨天)；

2、查询某个时间段的数据量:SELECT * FROM crawled_goods where created_at Between '2015-09-17 0:00:0' AND '2015-10-27 24:00:0';