優化MySQL查詢，因爲它會超時

任何人都可以幫助我優化此查詢。我無法執行它，因爲phpMyAdmin連接超時，我無法更改超時參數。優化MySQL查詢，因爲它會超時

下面是一個查詢：

INSERT INTO `goods` (`goods_id`, `price`, `name`) 
SELECT `sales_goods`.`goods_id`, `sales_goods`.`price`, `sales_goods`.`goods_id` 
FROM `sales_goods` 
WHERE `sales_goods`.`sales_goods_id` 
IN (
    SELECT MAX(`sales_goods`.`sales_goods_id`) 
    FROM `sales_goods` 
    WHERE `sales_goods`.`sales_goods_id` 
    IN (
     SELECT `sales_goods`.`sales_goods_id` FROM `sales_goods` 
     WHERE `sales_goods`.`goods_id` NOT IN (SELECT `goods`.`goods_id` FROM `goods`) 
    ) 
    GROUP BY `sales_goods`.`goods_id` 
)

來源

2013-04-25 Ellis

避免IN子句它是性能殺手...我的意思是嘗試將查詢更改爲JOINS而不是嵌套INs – 2013-04-25 10:25:17

即使在翻譯來自立陶宛語的查詢之後，它有點h想知道你想做什麼... – 2013-04-25 10:29:15

我同意，我無法理解它 - 我想我知道..但是這個MAX？！？ @ user2319233試圖解釋你的目標 – 2013-04-25 10:41:26

從確保你的表

除了在屬性格式索引可以用INNER JOIN取代你IN子查詢，以及LEFT JOIN/IS NULL你NOT IN子查詢，這應該提高性能：

INSERT INTO `goods` (`goods_id`, `price`, `name`) 
SELECT `sales_goods`.`goods_id`, 
     `sales_goods`.`price`, 
     `sales_goods`.`goods_id` 
FROM `sales_goods` 
     INNER JOIN 
     ( SELECT MAX(`sales_goods`.`sales_goods_id`) 
      FROM `sales_goods` 
        LEFT JOIN `goods` 
         ON `goods`.`goods_id` = `sales_goods`.`goods_id` 
      WHERE `goods`.`goods_id` IS NULL 
      GROUP BY `sales_goods`.`goods_id` 
     ) MaxSalesGoods 
      ON MaxSalesGoods.sales_goods_id = `sales_goods`.`sales_goods_id`

來源

2013-04-25 10:45:44 GarethD

謝謝，它有幫助 – Ellis 2013-04-25 12:24:25

優化MySQL查詢，因爲它會超時

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