[英]Is there an easier way to do this query in SQL and PHP
例如,我有下表,其中包含用户对产品的评论
tblreviews
ID | product | review|
==========================
1 | pen | 2 |
2 | pen | 2 |
3 | ink | 1 |
4 | ink | 1 |
我想编写一个查询,将每个项目的值加起来,然后给我前5名,在此示例中,我需要提取数据:
--
select sum (review) from tblreviews where product name= 'pen'
select count (pen) from tblreviews where product name= 'pen'
然后,我可以根据它们的结果来计算平均评论,但是我必须对表格中的每个产品进行此操作,然后再根据最高评论为我提供一个产品排名表,这就是我要尝试的结果得到。
这样做比较容易吗?
您可以使用分组依据
Select product, avg(review) as average
From tblreviews
Group by product
Order by average desc
Limit 5
平均评价排名前5的产品:
SELECT product, AVG(review) AS Average_review
FROM tblreviews
GROUP BY product
ORDER BY Average_review DESC
LIMIT 5
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