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我有这个非常慢的查询，它计算具有某些规格的产品，解决方案索引？或其他解决方案？

select count(DISTINCT if(ps10.specification in ('Meisje'),p.products_id,NULL)) as count1 ,count(DISTINCT if(ps10.specification in ('Jongen'),p.products_id,NULL)) as count2 ,count(DISTINCT if(ps10.specification in ('Unisex'),p.products_id,NULL)) as count3  from (products p)
                        join (products_to_categories p2c)
                          on (p.products_id = p2c.products_id)
                        left join (specials s)
                          on (p.products_id = s.products_id)
                        left join (products_attributes pa)
                          on (p.products_id = pa.products_id)
                        left join (products_options_values pv)
                          on (pa.options_values_id = pv.products_options_values_id)
                        left join (products_stock ps)
                          on (p.products_id=ps.products_id and pv.products_options_values_id = ps.products_options_values_id2)        
                                             INNER JOIN products_specifications ps10 ON p.products_id = ps10.products_id  INNER JOIN products_specifications ps17 ON p.products_id = ps17.products_id  where p.products_status = '1' and ps.products_stock_quantity>0   and p2c.categories_id in (2,54,60,82,109,115,116,118,53,58,104,55,101,75,56,64,66,67,68,69,70,71,84,103,114,80,92,99,93,94,95,97,106)  AND ps10.specifications_id = '10'
                  AND ps10.language_id = '1'
                   AND ps17.specification in ('Babyslofjes'
                              ) AND ps17.specifications_id = '17'
                  AND ps17.language_id = '1'

解释这个查询给了我这个结果：

+----+-------------+-------+--------+-------------------------------------+-------------------------------------+---------+------------------------------------------+-------+--------------------------+
| id | select_type | table |  type  |            possible_keys            |                 key                 | key_len |                   ref                    | rows  |          Extra           |
+----+-------------+-------+--------+-------------------------------------+-------------------------------------+---------+------------------------------------------+-------+--------------------------+
|  1 | SIMPLE      | ps    | ALL    | idx_products_stock_attributes       | NULL                                | NULL    | NULL                                     | 16216 | Using where              |
|  1 | SIMPLE      | p     | eq_ref | PRIMARY                             | PRIMARY                             | 4       | kikleding.ps.products_id                 |     1 | Using where              |
|  1 | SIMPLE      | s     | ref    | idx_specials_products_id            | idx_specials_products_id            | 4       | kikleding.p.products_id                  |     1 | Using index              |
|  1 | SIMPLE      | p2c   | ref    | PRIMARY                             | PRIMARY                             | 4       | kikleding.ps.products_id                 |     1 | Using where; Using index |
|  1 | SIMPLE      | pv    | ref    | PRIMARY                             | PRIMARY                             | 4       | kikleding.ps.products_options_values_id2 |     1 | Using where; Using index |
|  1 | SIMPLE      | ps10  | ref    | products_id                         | products_id                         | 12      | kikleding.p.products_id,const,const      |     1 | Using where              |
|  1 | SIMPLE      | ps17  | ref    | products_id                         | products_id                         | 12      | kikleding.ps.products_id,const,const     |     1 | Using where              |
|  1 | SIMPLE      | pa    | ref    | idx_products_attributes_products_id | idx_products_attributes_products_id | 4       | kikleding.p2c.products_id                |     6 | Using where              |
+----+-------------+-------+--------+-------------------------------------+-------------------------------------+---------+------------------------------------------+-------+--------------------------+

将左连接更改为内连接，如下所示：

select count(DISTINCT if(ps10.specification in ('Meisje'),p.products_id,NULL)) as count1 ,count(DISTINCT if(ps10.specification in ('Jongen'),p.products_id,NULL)) as count2 ,count(DISTINCT if(ps10.specification in ('Unisex'),p.products_id,NULL)) as count3  from (products p)
                        inner join (products_to_categories p2c)
                          on (p.products_id = p2c.products_id)
                        left join (specials s)
                          on (p.products_id = s.products_id)
                        inner join (products_attributes pa)
                          on (p.products_id = pa.products_id)
                        inner join (products_options_values pv)
                          on (pa.options_values_id = pv.products_options_values_id)
                        inner join (products_stock ps)
                          on (p.products_id=ps.products_id and pv.products_options_values_id = ps.products_options_values_id2)        
                                             INNER JOIN products_specifications ps10 ON p.products_id = ps10.products_id  INNER JOIN products_specifications ps17 ON p.products_id = ps17.products_id  where p.products_status = '1' and ps.products_stock_quantity>0   and p2c.categories_id in (2,54,60,82,109,115,116,118,53,58,104,55,101,75,56,64,66,67,68,69,70,71,84,103,114,80,92,99,93,94,95,97,106)  AND ps10.specifications_id = '10'
                  AND ps10.language_id = '1'
                   AND ps17.specification in ('Babyslofjes'
                              ) AND ps17.specifications_id = '17'
                  AND ps17.language_id = '1'

我索引了 ps.products_id

速度有点快，谢谢评论，但是查询还是很慢

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2 回答 2

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我会进行稍微修改的查询，以将条件从 where 部分放入连接中，并且从示例中我认为您也可以摆脱 Specials 表。

select
  count(distinct if(ps10.specification in ('Meisje'), p.products_id, null)) as count1,
  count(distinct if(ps10.specification in ('Jongen'), p.products_id, null)) as count2,
  count(distinct if(ps10.specification in ('Unisex'), p.products_id, null)) as count3
from (products p)
  inner join (products_to_categories p2c)
    on (p.products_id = p2c.products_id)
  inner join (products_attributes pa)
    on (p.products_id = pa.products_id)
  inner join (products_options_values pv)
    on (pa.options_values_id = pv.products_options_values_id)
  inner join (products_stock ps)
    on (p.products_id=ps.products_id and pv.products_options_values_id = ps.products_options_values_id2 and ps.products_stock_quantity > 0)        
  inner join products_specifications ps10
    ON p.products_id = ps10.products_id and ps10.language_id = '1' and ps10.specifications_id = '10'
  inner join products_specifications ps17
    ON p.products_id = ps17.products_id and ps17.language_id = '1' and ps17.specifications_id = '17'
where p.products_status = '1'
  and p2c.categories_id in (2,54,60,82,109,115,116,118,53,58,104,55,101,75,56,64,66,67,68,69,70,71,84,103,114,80,92,99,93,94,95,97,106)
  and ps17.specification in ('Babyslofjes')

至于索引，我会检查以下是否可用：

  • products / products_id （很可能是）
  • products_to_categories / products_id+categories_id （很可能也是）
  • products_attributes / products_id+options_values_id
  • products_options_values / products_options_values_id
  • products_specifications / products_id+language_id+specifications_id

从表名中我怀疑这是一个 OS/XTcommerce 数据库，我将尝试在几个小时内获得一个并给出更详细的意见。我只是不记得 products_stock 和 products_specifications，它们都是表，而不是视图，对吧？

于 2013-04-03T10:02:38.297 回答
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显然更多地使用 p.products_id，所以首先在表 Products 中索引该属性。然后 pv.products_options_values_id 并尝试索引您在 Inner Join 中使用的其他属性。还尝试转换要在 Join 条件中使用的条件，特别是 Inner join

于 2013-04-03T07:10:40.797 回答