解決 SQL 問題絕對能讓你對 MySQL 的理解更進一步!

sql教程欄目介紹如何更有效理解mysql

解決 SQL 問題絕對能讓你對 MySQL 的理解更進一步!

推薦(免費):sql教程

屬性表(product_props)結構如下

數據量800W以上

字段名 類型 說明
id int id
pn_id int 屬性類型
pv_id int 屬性值
product_id int 產品ID

其中product_id與pn_id,pv_id是一對多的關系。
數據類似這樣:

product_id pn_id pv_id
10970 5 ?(型號) 135 (蘋果9)
10970 11 ? ?(內存) 23 (512G)
10970 10 ? ?(顏色) 17 (土豪金)
10970 8 ? ?(網絡) 6(5G)
10980 5 135
10980 11 24 (1024G)
10980 10 16 (極光藍)

產品表(product)結構如下

數據量40W以上

字段名 類型 說明
product_id int product_id
type_id int 類型id
brand_id int 品牌id
model_id int 型號id
status tinyint 狀態

數據類似以下:

product_id type_id brand_id model_id status
10970 1(手機) 1(蘋果) 1(Iphone8) 1(正常)
10980 1(手機) 1(蘋果) 1(Iphone8X) 3(已售)
10981 1(手機) 1(蘋果) 1(Iphone8XP) 1(正常)

問題

找出型號為蘋果9同時內存為512G,顏色為土豪金,狀態為正常產品總數
ps : 屬性條件可能會有超過10組。

要求

性能第一,杜絕聚合函數等

原問題的解決方案性能排行

  1. 來自 @Kamicloud的 exist方案
SELECT      sql_no_cache `product_id` FROM     `zx_tests` AS a WHERE     `pn_id` = 101 AND `pv_id` = 59         AND EXISTS( SELECT             sql_no_cache  *         FROM             `zx_tests`         WHERE         a.product_id = product_id and             `pn_id` = 101 AND `pv_id` = 171);      2 組條件下 0.657,3 組 0.695,4 組 0.759,5 組 0.743 (單獨查屬性表)
  1. 來自 @Elijah_Wang的子查詢方案
SELECT `product_id` FROM `product` WHERE `pn_id` = 5 AND `pv_id` = 135 AND `product_id` IN (SELECT `product_id` FROM `product` WHERE `pn_id` = 11 AND `pv_id` = 23);      2 組條件下 0.729,3 組 0.75,4 組 0.730,5 組 0.757 (新問題之前)

新問題之后的性能排行

  1. 來自 @Elijah_Wang的子查詢方案
    select SQL_NO_CACHE count(1) from pdi_product a join  (         SELECT              distinct product_id         FROM             `product_props`          WHERE             `pn_id` = 5              AND `pv_id` = 127             AND `product_id` IN ( SELECT  `product_id` FROM `product_props` WHERE `pn_id` = 11 AND `pv_id` = 22 )              AND `product_id` IN ( SELECT  `product_id` FROM `product_props` WHERE `pn_id` = 10 AND `pv_id` = 18 )              AND `product_id` IN ( SELECT  `product_id` FROM `product_props` WHERE `pn_id` = 8 AND `pv_id` = 6 )               AND `product_id` IN ( SELECT  `product_id` FROM `product_props` WHERE `pn_id` = 9 AND `pv_id` = 1 )             ) b on a.product_id = b.product_id              where  a.status = 1;

耗時1.5-1.56 (執行10次的范圍)

  • expain分析:

解決 SQL 問題絕對能讓你對 MySQL 的理解更進一步!

        select SQL_NO_CACHE count(1) from pdi_product a              where  a.status = 1 and a.product_id in (SELECT              distinct product_id         FROM             `product_props`          WHERE             `pn_id` = 5              AND `pv_id` = 127             AND `product_id` IN ( SELECT  `product_id` FROM `product_props` WHERE `pn_id` = 11 AND `pv_id` = 22 )              AND `product_id` IN ( SELECT  `product_id` FROM `product_props` WHERE `pn_id` = 10 AND `pv_id` = 18 )              AND `product_id` IN ( SELECT  `product_id` FROM `product_props` WHERE `pn_id` = 8 AND `pv_id` = 6 )               AND `product_id` IN ( SELECT  `product_id` FROM `product_props` WHERE `pn_id` = 9 AND `pv_id` = 1 ))

耗時0.69-0.72(執行10次的范圍)

  • explain分析:
    解決 SQL 問題絕對能讓你對 MySQL 的理解更進一步!
  1. 來自 @Kamicloud的 exist方案
    SELECT SQL_NO_CACHE             count(1)          FROM             product a         WHERE             a.STATUS = 1              AND a.product_id IN (         SELECT DISTINCT             `product_id`          FROM             `product_props` AS a          WHERE             a.`pn_id` = 5              AND a.`pv_id` = 127              AND EXISTS ( SELECT product_id FROM `product_props` WHERE a.product_id = product_id AND `pn_id` = 11 AND `pv_id` = 22 )              AND EXISTS ( SELECT product_id FROM `product_props` WHERE a.product_id = product_id AND `pn_id` = 10 AND `pv_id` = 18 )              AND EXISTS ( SELECT product_id FROM `product_props` WHERE a.product_id = product_id AND `pn_id` = 9 AND `pv_id` = 1 )              AND EXISTS ( SELECT product_id FROM `product_props` WHERE a.product_id = product_id AND `pn_id` = 8 AND `pv_id` = 6 )              );

耗時5.7-5.85 (執行10次的范圍)

  • explain分析:

解決 SQL 問題絕對能讓你對 MySQL 的理解更進一步!

    SELECT SQL_NO_CACHE         count(1)      FROM         pdi_product a         join (SELECT DISTINCT         `product_id`      FROM         `product_props` AS a      WHERE         a.`pn_id` = 5          AND a.`pv_id` = 127          AND EXISTS ( SELECT product_id FROM `product_props` WHERE a.product_id = product_id AND `pn_id` = 11 AND `pv_id` = 22 )          AND EXISTS ( SELECT product_id FROM `product_props` WHERE a.product_id = product_id AND `pn_id` = 10 AND `pv_id` = 18 )          AND EXISTS ( SELECT product_id FROM `product_props` WHERE a.product_id = product_id AND `pn_id` = 9 AND `pv_id` = 1 )          AND EXISTS ( SELECT product_id FROM `product_props` WHERE a.product_id = product_id AND `pn_id` = 8 AND `pv_id` = 6 ) ) b     on a.product_id = b.product_id     WHERE         a.STATUS = 1

耗時5.7-6.0(執行10次的范圍)

  • explain分析:

解決 SQL 問題絕對能讓你對 MySQL 的理解更進一步!


可以看到如果單純查屬性表,第一位的速度是最快的,可要查產品狀態后,速度反而不如子查詢。

經explain分析,第一個子查詢速度之所以快是因為它的sql簡單,select_type皆為simple。

而不管是join還是exists的方式,select_type大多為DERIVED,DEPENDENT SUBQUERY。

相關免費學習推薦:mysql視頻教程

? 版權聲明
THE END
喜歡就支持一下吧
點贊9 分享