我正在帮助一个拥有电子商务网站的朋友。他可以选择用户选择他销售的产品的不同颜色，款式，用途和类型。查询将以下内容添加到查询中：
INNER JOIN tbl_coloursProducts col ON ( p.product_id = col.productID AND (col.colourID = 2 OR col.colourID = 3 OR col.colourID = 5 OR col.colourID = 8 OR col.colourID = 10))
INNER JOIN tbl_useProducts tbluse ON ( p.product_id = tbluse.productID AND (tbluse.useID = 15 OR tbluse.useID = 16 OR tbluse.useID = 17 OR tbluse.useID = 18))
INNER JOIN tbl_styleProducts style ON ( p.product_id = style.productID AND (style.styleID = 39 OR style.styleID = 44))
INNER JOIN tbl_typeProducts type ON ( p.product_id = type.productID AND (type.typeID = 46 OR type.typeID = 48 OR type.typeID = 50))
当只有少数几个选项正在选择时，查询加载速度足够快，但有些用户正在选择多个或每个选项导致查询运行超过30秒并超时。
如果不改变表结构，是否有更好的方法来优化查询？
这是完整的查询：
SELECT *,
p.product_id,
Coalesce((SELECT p2sp.price
FROM ab_product_specials p2sp
WHERE p2sp.product_id = p.product_id
AND p2sp.customer_group_id = '1'
AND ( ( p2sp.date_start = '0000-00-00'
OR p2sp.date_start < Now() )
AND ( p2sp.date_end = '0000-00-00'
OR p2sp.date_end > Now() ) )
ORDER BY p2sp.priority ASC,
p2sp.price ASC
LIMIT 1), p.price) AS final_price,
pd.name AS name,
m.name AS manufacturer,
ss.name AS stock,
(SELECT Avg(r.rating)
FROM ab_reviews r
WHERE p.product_id = r.product_id
GROUP BY r.product_id) AS rating,
(SELECT Count(rw.review_id)
FROM ab_reviews rw
WHERE p.product_id = rw.product_id
GROUP BY rw.product_id) AS review
FROM ab_products p
LEFT JOIN ab_product_descriptions pd
ON ( p.product_id = pd.product_id
AND pd.language_id = '1' )
LEFT JOIN ab_products_to_stores p2s
ON ( p.product_id = p2s.product_id )
LEFT JOIN ab_manufacturers m
ON ( p.manufacturer_id = m.manufacturer_id )
LEFT JOIN ab_stock_statuses ss
ON ( p.stock_status_id = ss.stock_status_id
AND ss.language_id = '1' )
LEFT JOIN ab_products_to_categories p2c
ON ( p.product_id = p2c.product_id )
INNER JOIN tbl_coloursproducts col
ON ( p.product_id = col.productid
AND ( col.colourid = 2
OR col.colourid = 3
OR col.colourid = 5
OR col.colourid = 8
OR col.colourid = 10 ) )
INNER JOIN tbl_useproducts tbluse
ON ( p.product_id = tbluse.productid
AND ( tbluse.useid = 15
OR tbluse.useid = 16
OR tbluse.useid = 17
OR tbluse.useid = 18 ) )
INNER JOIN tbl_styleproducts style
ON ( p.product_id = style.productid
AND ( style.styleid = 39
OR style.styleid = 44 ) )
INNER JOIN tbl_typeproducts type
ON ( p.product_id = type.productid
AND ( type.typeid = 46
OR type.typeid = 48
OR type.typeid = 50 ) )
WHERE p.status = '1'
AND p.date_available <= Now()
AND p2s.store_id = 0
AND p2c.category_id = 131
GROUP BY p.product_id
ORDER BY p.product_id DESC
LIMIT 0, 8
没有自定义位，查询运行正常。
答案 0 :(得分：0)
查看该查询，不确定OR本身是否存在问题（尽管您可以通过对每个问题使用和IN子句使代码更紧凑）。相反，我怀疑选择越来越多的选项会导致返回更多行。这导致SELECT子句中的子查询出现问题。
您是否可以使用从SELECT子句中删除的子查询来尝试查询，并查看具有的效果。
您可以非常轻松地删除子查询。
SELECT *,
p.product_id,
Coalesce(sub1.price, p.price) AS final_price,
pd.name AS name,
m.name AS manufacturer,
ss.name AS stock,
sub0.rating,
sub0.review
FROM ab_products p
INNER JOIN
(
SELECT r.product_id,
Avg(r.rating) AS rating,
Count(rw.review_id) AS review
FROM ab_reviews r
GROUP BY r.product_id
) sub0
ON p.product_id = sub0.product_id
LEFT OUTER JOIN
(
SELECT p2sp.product_id,
SUBSTRING_INDEX(GROUP_CONCAT(p2sp.price ORDER BY p2sp.priority ASC, p2sp.price ASC ), ',', 1) AS price
FROM ab_product_specials p2sp
WHERE p2sp.customer_group_id = '1'
AND ( p2sp.date_start = '0000-00-00' OR p2sp.date_start < NOW() )
AND ( p2sp.date_end = '0000-00-00' OR p2sp.date_end > NOW() )
GROUP BY p2sp.product_id
) sub1
ON p.product_id = sub1.product_id
LEFT JOIN ab_product_descriptions pd
ON ( p.product_id = pd.product_id
AND pd.language_id = '1' )
LEFT JOIN ab_products_to_stores p2s
ON ( p.product_id = p2s.product_id )
LEFT JOIN ab_manufacturers m
ON ( p.manufacturer_id = m.manufacturer_id )
LEFT JOIN ab_stock_statuses ss
ON ( p.stock_status_id = ss.stock_status_id
AND ss.language_id = '1' )
LEFT JOIN ab_products_to_categories p2c
ON ( p.product_id = p2c.product_id )
INNER JOIN tbl_coloursproducts col
ON ( p.product_id = col.productid
AND ( col.colourid = 2
OR col.colourid = 3
OR col.colourid = 5
OR col.colourid = 8
OR col.colourid = 10 ) )
INNER JOIN tbl_useproducts tbluse
ON ( p.product_id = tbluse.productid
AND ( tbluse.useid = 15
OR tbluse.useid = 16
OR tbluse.useid = 17
OR tbluse.useid = 18 ) )
INNER JOIN tbl_styleproducts style
ON ( p.product_id = style.productid
AND ( style.styleid = 39
OR style.styleid = 44 ) )
INNER JOIN tbl_typeproducts type
ON ( p.product_id = type.productid
AND ( type.typeid = 46
OR type.typeid = 48
OR type.typeid = 50 ) )
WHERE p.status = '1'
AND p.date_available <= Now()
AND p2s.store_id = 0
AND p2c.category_id = 131
GROUP BY p.product_id
ORDER BY p.product_id DESC
LIMIT 0, 8
顺便说一下，当您从ab_product_specials读取时，您正在检查date_start和date_end是否为0000-00-00（即日期），还要将它们与返回日期/时间字段的NOW（）进行比较。这些字段是日期还是日期/时间字段？
答案 1 :(得分：0)
我的第一个问题是使用~/.xinitrc使查询更容易阅读：
IN然后我想，我想知道他们是否动态构建SQL文本以喷入数据库逻辑？！优化器在以这种方式不断变异时优化查询的可能性不大。
考虑临时表（伪代码）：
INNER JOIN tbl_coloursProducts col
ON p.product_id = col.productID AND col.colourID IN ( 2, 3, 5, 8, 10 )
现在，动态值列表只是另一个连接：
-- One time:
CREATE TABLE SratchColours ( colourID INT NOT NULL UNQIUE );
-- For each query:
DELETE FROM SratchColours;
INSERT INTO SratchColours VALUES ( 2 ), ( 3 ), ( 5 ), ( 8 ), ( 10 );
（如果必须的话，你可以使用内部联接！）
现在，为每个并发用户提供一个基表可能不是扩展系统的好方法。因此，考虑如何将一包tbl_coloursProducts NATURAL JOIN SratchColours
值传递给数据库逻辑（例如，存储过程），将它们放入表（例如，临时表）中，然后从那里连接到基表。 / p>