Mysql query execution order

order:

• FROM
• JOIN
• ON
• WHERE
• GROUP BY (从此处开始可以使用select中指定的别名)
• AVG, SUM, MAX
• HAVING
• SELECT
• DISTINCT
• ORDER BY

select  
   sum(goods.number)  
from order 
left join goods on goods.order_id = order.id 
where 
  order.status=1 
  group by order.user_id 
  having order.add_time > '2019-08-27 00:00:00' order by goods.number desc

 

• First order to obtain data from the Orders table inside
• Then ligated into a field through the left join more tables and line appearances commodity
• By screening out the order status where the data 1
• by user group by group, to obtain the user's purchase quantity and
• In the above screening data, select the data in order to create time after August 27, 2019 in
• Finally, these data to get the final data results in descending order by number of items purchased