sql - 在 SQLite 中删除低于给定平均值的项目：我收到语法错误

Question

我有一张很大的桌子。

每行都有一个 uniqueId 和一个 itemId。我想删除价格低于给定平均值的所有项目。我认为这样的事情应该可以工作，但它没有：

 DELETE FROM items GROUP BY itemId HAVING avg(price) < ?

SQLite 抱怨：

“GROUP”附近：语法错误

知道会发生什么吗？

Answer 1

DELETE 
FROM items as i1 
WHERE i1.itemID in (
    Select i2.itemID 
    FROM items as i2
    GROUP BY i2.itemId 
    HAVING avg(price) < "user defined threshold" )

Answer 2

试试这个：

delete I 
from   items I join
       (select itemId,avg(price) as price
       from items
       GROUP BY itemId)a
on     I.itemId=a.itemId
where  I.price<a.price

Answer 3

我认为应该是这样的

DELETE FROM items WHERE itemId HAVING avg(price) < ?