mysql获取规定时间段内统计数据的方法教程

SELECT 
  count(*), 
  DATE_FORMAT(order_info.create_time, '%Y-%m-%d') AS count_by_date 
FROM 
  order_info 
WHERE 
  DATE_FORMAT(order_info.create_time, '%Y') = '2017' 
GROUP BY 
  count_by_date 
ORDER BY NULL

SELECT 
  count(*), 
  DATE_FORMAT(order_info.create_time, '%Y-%m-%d') AS count_by_date 
FROM 
  order_info 
WHERE 
  DATE_FORMAT(order_info.create_time, '%Y-%m') = '2017-04' 
GROUP BY 
  count_by_date 
ORDER BY NULL