Mysql 在多个表上选择“最大值”，不进行两次计数_Mysql_Sql

Mysql 在多个表上选择“最大值”，不进行两次计数

mysql sql

Mysql 在多个表上选择“最大值”，不进行两次计数,mysql,sql,Mysql,Sql,我正在做一个查询，允许我按分数订购食谱表结构结构是，传单包含一个或多个传单项目，可以包含一个或多个成分（此表将成分链接到传单项目）。另一个表配料到配方链接了相同的配料，但链接到一个或多个配方。最后包含指向.sql文件的链接示例查询我想得到配方id和配方中每种成分的最大价格权重之和（由成分链接到配方），但如果一个配方中有多个成分属于同一传单项目，则应计算一次 SELECT itr.recipe_id, SUM(itr.weight), SUM(max_price

我正在做一个查询，允许我按分数订购食谱

表结构结构是，传单包含一个或多个

传单项目

，可以包含一个或多个

成分

（此表将成分链接到传单项目）。另一个表

配料到配方

链接了相同的配料，但链接到一个或多个配方。最后包含指向.sql文件的链接

示例查询我想得到配方id和配方中每种成分的最大价格权重之和（由成分链接到配方），但如果一个配方中有多个成分属于同一传单项目，则应计算一次

SELECT itr.recipe_id,
       SUM(itr.weight),
       SUM(max_price_weight),
       SUM(itr.weight + max_price_weight) AS score
FROM
  ( SELECT MAX(itf.max_price_weight) AS max_price_weight,
           itf.flyer_item_id,
           itf.ingredient_id
   FROM
     (SELECT ifi.ingredient_id,
             MAX(i.price_weight) AS max_price_weight,
             ifi.flyer_item_id
      FROM flyer_items i
      JOIN ingredient_to_flyer_item ifi ON i.id = ifi.flyer_item_id
      WHERE i.flyer_id IN (1,
                           2)
      GROUP BY ifi.ingredient_id ) itf
   GROUP BY itf.flyer_item_id) itf2
JOIN `ingredient_to_recipe` AS itr ON itf2.`ingredient_id` = itr.`ingredient_id`
WHERE recipe_id = 5730
GROUP BY itr.`recipe_id`
ORDER BY score DESC
LIMIT 0,10

查询几乎可以正常工作，因为大多数结果都是好的，但是对于某些行，一些成分被忽略，并且没有从分数中计算出来

测试用例我很难找到一个简单的解释方法。如果还有什么可以帮忙的，请告诉我

以下是指向演示数据库的链接，用于运行查询、测试示例和测试用例：

多谢各位

更新（如Rick James所问）：这是我能做的最远的事了。结果总是很好的，在子查询中也是如此，但是，我已经完全按照“flyer\u item\u id”删除了组。通过这个查询，我得到了好的分数，但是如果配方中的许多成分是相同的传单项目，它们将被计数多次（比如配方id=10557的分数是59，而不是好的56，因为价值3的2种成分在相同的传单项目中）。我唯一需要更多的是计算每个配方的每个传单项目id的最大值（价格重量）（我最初尝试通过“传单项目id”分组，而不是通过成分id分组）

SELECT itr.recipe_id,
       SUM(itr.weight) as total_ingredient_weight,
       SUM(itf.price_weight) as total_price_weight,
       SUM(itr.weight+itf.price_weight) as score
FROM
  (SELECT fi1.id, MAX(fi1.price_weight) as price_weight, ingredient_to_flyer_item.ingredient_id as ingredient_id, recipe_id
FROM flyer_items fi1
INNER JOIN (
    SELECT flyer_items.id as id, MAX(price_weight) as price_weight, ingredient_to_flyer_item.ingredient_id as ingredient_id
    FROM flyer_items
    JOIN ingredient_to_flyer_item ON flyer_items.id = ingredient_to_flyer_item.flyer_item_id
    GROUP BY id
) fi2 ON fi1.id = fi2.id AND fi1.price_weight = fi2.price_weight
JOIN ingredient_to_flyer_item ON fi1.id = ingredient_to_flyer_item.flyer_item_id
JOIN ingredient_to_recipe ON ingredient_to_flyer_item.ingredient_id = ingredient_to_recipe.ingredient_id
GROUP BY ingredient_to_flyer_item.ingredient_id) AS itf
INNER JOIN `ingredient_to_recipe` AS `itr` ON `itf`.`ingredient_id` = `itr`.`ingredient_id`
GROUP BY `itr`.`recipe_id`
ORDER BY `score` DESC
LIMIT 10

下面是解释，但我不确定它是否有用，因为最后一个工作部分仍然缺失：

| id | select_type | table                    | partitions | type   | possible_keys                 | key           | key_len | ref                                                   | rows   | filtered | Extra                           |   |
|----|-------------|--------------------------|------------|--------|-------------------------------|---------------|---------|-------------------------------------------------------|--------|----------|---------------------------------|---|
| 1  | PRIMARY     | itr                      | NULL       | ALL    | recipe_id,ingredient_id       | NULL          | NULL    | NULL                                                  | 151800 | 100.00   | Using temporary; Using filesort |   |
| 1  | PRIMARY     | <derived2>               | NULL       | ref    | <auto_key0>                   | <auto_key0>   | 4       | metadata3.itr.ingredient_id                           | 10     | 100.00   | NULL                            |   |
| 2  | DERIVED     | ingredient_to_flyer_item | NULL       | ALL    | NULL                          | NULL          | NULL    | NULL                                                  | 249    | 100.00   | Using temporary; Using filesort |   |
| 2  | DERIVED     | fi1                      | NULL       | eq_ref | id_2,id,price_weight          | id_2          | 4       | metadata3.ingredient_to_flyer_item.flyer_item_id      | 1      | 100.00   | NULL                            |   |
| 2  | DERIVED     | <derived3>               | NULL       | ref    | <auto_key0>                   | <auto_key0>   | 9       | metadata3.ingredient_to_flyer_item.flyer_item_id,m... | 10     | 100.00   | NULL                            |   |
| 2  | DERIVED     | ingredient_to_recipe     | NULL       | ref    | ingredient_id                 | ingredient_id | 4       | metadata3.ingredient_to_flyer_item.ingredient_id      | 40     | 100.00   | NULL                            |   |
| 3  | DERIVED     | ingredient_to_flyer_item | NULL       | ALL    | NULL                          | NULL          | NULL    | NULL                                                  | 249    | 100.00   | Using temporary; Using filesort |   |
| 3  | DERIVED     | flyer_items              | NULL       | eq_ref | id_2,id,flyer_id,price_weight | id_2          | 4       | metadata3.ingredient_to_flyer_item.flyer_item_id      | 1      | 100.00   | NULL                            |   |

以下是解释：

| id | select_type | table                    | partitions | type  | possible_keys                                | key           | key_len | ref                 | rows | filtered | Extra                           |   |
|----|-------------|--------------------------|------------|-------|----------------------------------------------|---------------|---------|---------------------|------|----------|---------------------------------|---|
| 1  | PRIMARY     | <derived2>               | NULL       | ALL   | NULL                                         | NULL          | NULL    | NULL                | 1318 | 100.00   | Using temporary; Using filesort |   |
| 2  | DERIVED     | <derived4>               | NULL       | ALL   | NULL                                         | NULL          | NULL    | NULL                | 37   | 100.00   | Using temporary                 |   |
| 2  | DERIVED     | itr                      | NULL       | ref   | ingredient_id                                | ingredient_id | 4       | itfin.ingredient_id | 35   | 100.00   | NULL                            |   |
| 4  | DERIVED     | <derived5>               | NULL       | ALL   | NULL                                         | NULL          | NULL    | NULL                | 249  | 100.00   | Using temporary; Using filesort |   |
| 4  | DERIVED     | ifi1                     | NULL       | ref   | ingredient_id,itx_full,price_weight,flyer_id | ingredient_id | 4       | ifi2.ingredient_id  | 1    | 12.50    | Using where                     |   |
| 5  | DERIVED     | ingredient_to_flyer_item | NULL       | index | ingredient_id,itx_full                       | ingredient_id | 4       | NULL                | 249  | 100.00   | NULL                            |   |

| id |选择|类型|表格|分区|类型|可能的|键|键|列|参考|行|过滤|额外||
|----|-------------|--------------------------|------------|-------|----------------------------------------------|---------------|---------|---------------------|------|----------|---------------------------------|---|
|1 | PRIMARY | NULL | ALL | NULL | NULL | NULL | NULL | 1318 | 100.00 |使用临时；使用文件排序||
|2 |派生|空|所有|空|空|空|空| 37 | 100.00 |使用临时||
|2 |派生| itr | NULL | ref |配料| id |配料| id | 4 | itfin.配料| id | 35 | 100.00 | NULL ||
|4 |派生| | NULL | ALL | NULL | NULL | NULL | NULL | 249 | 100.00 |使用临时；使用文件排序||
|4 |派生| ifi1 |空|参考|成分id，itx |完整，价格|重量，传单| id |成分| id | 4 | ifi2.成分| id | 1 | 12.50 |使用where ||
|5 |衍生|成分|到|传单|项目|空|索引|成分| id，itx |完整|成分| id | 4 |空| 249 | 100.00 |空||

我不确定自己是否完全理解了这个问题。在我看来，您按错误的列

传单项目.id

进行分组。您应该改为按列

成分id

进行分组。如果您这样做，它（对我）更有意义。以下是我的看法：

select
    itr.recipe_id,
    sum(itr.weight),
    sum(max_price_weight),
    sum(itr.weight + max_price_weight) as score
  from (
    select
        ifi.ingredient_id, 
        max(price_weight) as max_price_weight
      from flyer_items i
      join ingredients_to_flyer_item ifi on i.id = ifi.flyer_item_id
      where flyer_id in (1, 2)
      group by ifi.ingredient_id
    ) itf
  join `ingredient_to_recipe` as itr on itf.`ingredient_id` = itr.`ingredient_id`
  group by itr.`recipe_id`
  order by score desc
  limit 0,10;

我希望它能有所帮助。

听起来像是“爆炸内爆”。这就是查询的

连接和分组方式
JOIN
从连接的表中收集适当的行组合；然后
分组依据
计数
，求和
等，为聚合提供膨胀值
有两种常见的修复方法，都涉及将聚合与连接分开进行
案例1：
SELECT  ...
        ( SELECT SUM(x) FROM t2 WHERE id = ... ) AS sum_x,
        ...
    FROM t1 ...

如果您需要来自t2的多个聚合，那么这种情况会变得很笨拙，因为它一次只允许一个聚合
案例2：
SELECT ...
    FROM ( SELECT grp,
                  SUM(x) AS sum_x,
                  COUNT(*) AS ct
           FROM t2 ) AS s
    JOIN t1 ON t1.grp = s.grp

您有2个连接
和3个分组方式
，因此我建议您从内到外调试（并重写）查询
        SELECT  ifi.ingredient_id,
                MAX(price_weight) as max_price_weight,
                flyer_item_id
            from  flyer_items i
            join  ingredient_to_flyer_item ifi  ON i.id = ifi.flyer_item_id
            where  flyer_id in (1, 2)
            group by  ifi.ingredient_id 

但是我帮不了你，因为你没有根据它所在的表（或别名）限定price\u weight
（其他一些列也一样）
（实际上，MAX
和MIN
不会得到夸大的值；AVG
会得到稍微错误的值；COUNT
和SUM
会得到“错误”的值。）
因此，我将把其余部分作为“练习”留给读者”
索引
itr:  (ingredient_id, recipe_id)  -- for the JOIN and WHERE and GROUP BY
itr:  (recipe_id, ingredient_id, weight)  -- for 1st Update
(There is no optimization available for the ORDER BY and LIMIT)
flyer_items:  (flyer_id, price_weight) -- unless flyer_id is the PRIMARY KEY
ifi:  (flyer_item_id, ingredient_id)
ifi:  (ingredient_id, flyer_item_id)  -- for 1st Update

请为相关表格提供“显示创建表格”
请提供解释选择…

如果配料到传单项目
是一个多：多映射表，请按照提示操作。配料到配方

按itf分组。传单项目id
可能无效，因为它不包括非聚合的ifi.成分id
。请参阅“仅按完整分组”
重新编制
完成对索引的评估后，请尝试以下操作。注意：我不知道它是否能正常工作
到
并更改初始的SELECT
以将SUMs
替换为这些计算出的总和。（我怀疑我没有正确处理成分id
）
什么版本
        SELECT  ifi.ingredient_id,
                MAX(price_weight) as max_price_weight,
                flyer_item_id
            from  flyer_items i
            join  ingredient_to_flyer_item ifi  ON i.id = ifi.flyer_item_id
            where  flyer_id in (1, 2)
            group by  ifi.ingredient_id 

itr:  (ingredient_id, recipe_id)  -- for the JOIN and WHERE and GROUP BY
itr:  (recipe_id, ingredient_id, weight)  -- for 1st Update
(There is no optimization available for the ORDER BY and LIMIT)
flyer_items:  (flyer_id, price_weight) -- unless flyer_id is the PRIMARY KEY
ifi:  (flyer_item_id, ingredient_id)
ifi:  (ingredient_id, flyer_item_id)  -- for 1st Update

JOIN  `ingredient_to_recipe` AS itr  ON itf2.`ingredient_id` = itr.`ingredient_id`

JOIN ( SELECT recipe_id,
              ingredient_id,
              SUM(weight) AS sum_weight
           FROM ingredient_to_recipe ) AS itr

SELECT recipe_id, SUM(weight) AS weight, SUM(max_price_weight) AS price_weight, SUM(weight + max_price_weight) AS score 
FROM (SELECT recipe_id, ingredient_id, MAX(weight) AS weight, MAX(price_weight) AS max_price_weight
      FROM (SELECT itr.recipe_id, MIN(itr.ingredient_id) AS ingredient_id, MAX(itr.weight) AS weight, fi.id, MAX(fi.price_weight) AS price_weight
            FROM ingredient_to_recipe itr 
            JOIN ingredient_to_flyer_item itfi ON itfi.ingredient_id = itr.ingredient_id 
            JOIN flyer_items fi ON fi.id = itfi.flyer_item_id 
            GROUP BY itr.recipe_id, fi.id) ri
      GROUP BY recipe_id, ingredient_id) r
GROUP BY recipe_id
ORDER BY score DESC
LIMIT 10

HAVING recipe_id IN (8376, 3152, 4771, 10230, 8958, 4656, 11338)

recipe_id   weight  price_weight    score   
8376        10      41              51
4771        5       40              45
10230       10      30              40
8958        15      24              39
4656        15      19              34
3152        0       18              18
11338       0       10              10