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這篇文章主要介紹了使用 MySQL 的示例分析,具有一定借鑒價值,感興趣的朋友可以參考下,希望大家閱讀完這篇文章之后大有收獲,下面讓丸趣 TV 小編帶著大家一起了解一下。
屬性表 (product_props) 結構如下
數據量 800W 以上
字段名類型說明 idintidpn_idint 屬性類型 pv_idint 屬性值 product_idint 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_idpn_idpv_id109705 (型號)135(蘋果 9)1097011 (內存)23(512G)1097010 (顏色)17(土豪金)109708 (網絡)6(5G)109805135109801124(1024G)109801016(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_idintproduct_idtype_idint 類型 idbrand_idint 品牌 idmodel_idint 型號 idstatustinyint 狀態
數據類似以下:
product_idtype_idbrand_idmodel_idstatus109701(手機)1(蘋果)1(Iphone8)1(正常)109801(手機)1(蘋果)1(Iphone8X)3(已售)109811(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,狀態為正常的產品總數,
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
來自 @Kamicloud 的 exist 方案
SELECT
sql_no_cache `product_id`
`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)
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
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:
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:
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:
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:
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。
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