使用 LIMIT 从 MySQL 表中选择平均值
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Select average from MySQL table with LIMIT
提问by James Simpson
I am trying to get the average of the lowest 5 priced items, grouped by the username attached to them. However, the below query gives the average price for each user (which of course is the price), but I just want one answer returned.
我试图获得价格最低的 5 个商品的平均值，按附加到它们的用户名分组。但是，下面的查询给出了每个用户的平均价格（当然是价格），但我只想返回一个答案。
SELECT AVG(price)
FROM table
WHERE price > '0' && item_id = '$id'
GROUP BY username
ORDER BY price ASC
LIMIT 5
回答by OMG Ponies
I think this is what you're after:
我认为这就是你所追求的：
SELECT AVG(items.price)
FROM (SELECT t.price
FROM TABLE t
WHERE t.price > '0'
AND t.item_id = '$id'
ORDER BY t.price
LIMIT 5) items
It will return the average of the 5 lowest prices - a single answer.
它将返回 5 个最低价格的平均值 - 一个答案。
回答by Aman Dhadwal
Simple solution below.
下面简单解决。
Query:
询问：
SELECT AVG(Column_name)
FROM (SELECT Column_name
FROM Table
WHERE ColumnID < number[Limit you want] )
