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如何优化三重加入这样的查询的MySQL查询优化三重加入VS嵌套查询
select users.id_user from users,sales,specSales where users.id_user=sales.id_user AND sales.id_sale=specSales.id_sale AND specSales.id_article=34 group by id_user
我想谁买由id_article标识的产品不同用户= X
我想过这个,但我不保证改善
select id_user from (select distinct(sales.id_user) from sales,specSales where sales.id_sale=specordine.id_sale and specSale.id_article=34)as t
表是(* =主键)
的0users
*id_user | name | ....
sales
*id_sale | id_user | .... other values
salesSpec
id_sale | id_article | .... other values
许多由于
第一个查询不工作还是很慢? – 2012-08-08 18:56:17