价格 id id_stock价格日期
**stocks**
id
stock_name
active
现在我必须stocks.active=0为每个拥有MAX(prices.date) > 15 days(我必须通过的日期)的股票设置
这是我的查询,但它非常慢!
update stocks set stocks.active=0 where stocks.id IN (
SELECT prices.id_stock
FROM prices
GROUP BY prices.id_stock
HAVING datediff('2010-08-17', MAX( prices.date )) > 15
)
如何优化呢？
非常感谢你!