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如何優化三重加入這樣的查詢的MySQL查詢優化三重加入VS嵌套查詢
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
我想誰買由id_article標識的產品不同用戶= X
我想過這個,但我不保證改善
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(* =主鍵)
的0users
*id_user | name | ....
sales
*id_sale | id_user | .... other values
salesSpec
id_sale | id_article | .... other values
許多由於
第一個查詢不工作還是很慢? – 2012-08-08 18:56:17