具有SQLite中多个条件和列的AVG函数

问题描述 投票：1回答：2

我想出了如何用条件/ s做avg函数，但我不能让它适合我的特定需要。假设我正在使用名为sales_performance的表

  product_ID  sales_period  sales_qty  sales_index  product_sub goal_met
         C12          0001         15           20          D71        Y
         D71          0001         07           09          C12        N
         F20          0001         25           30          C05        Y
         C05          0001         10           15          F20        N
         C12          0002         15           30          C05        Y
         C05          0002         12           06          C12        N
         D71          0002         30           20          F20        Y
         F20          0002         20           15          D71        N
         C12          0003         05           04          F20        N
         F20          0003         40           35          C12        Y
         D71          0003         20           20          C05        Y
         C05          0003         12           10          D71        N

我想为产品C12计算一个名为sales_index_goal的新值。然后，该值的公式为：

sales_index产品'C12'的平均值Goal_Met = 'Y'和sales_index的sub_product当Goal_Met = 'N'在那之前的销售期间。

因此，例如，如果我想为'C12' sales_period计算产品0003的sales_index_goal，则计算如下：

平均值（30，20，15）其中30和20是产品sales_index的'C12'es在销售期1和2和15是产品sales_index在销售期'F20'的2。

我在确切的销售期间计算这个值没有任何问题。但是，我很难想出一个查询，为所有销售期计算产品'C12'的这个值。目前，我写的这个查询不起作用：

SELECT 
    s.*, 
    AVG(CASE 
        WHEN s2.goal_met = "Y" AND s2.product_id = "C2" 
            THEN s2.sales_index 
        WHEN s2.product_id = (
            SELECT s2.product_sub WHERE s2.product_id = "C12"
        ) AND s2.goals_met = "N" 
            THEN s2.sales_index
        ELSE NULL 
    END)
    OVER (
        ORDER BY s.sales_period 
        ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING
    ) AS sales_index_goal
FROM 
    sales_performance s, 
    sales_performance s2
WHERE s.product_id = "C12"

我真的很感激任何帮助。额外奖励：计算所有销售期间所有产品的此值。

编辑：以下答案适用于计算产品C12的sales_index_goal但是，它不适用于产品F20（更详细的原因，为什么它不起作用是在我的评论下面的答案）你可以看到查询的结果产品F20 here

sql sqlite conditional average
2个回答
1
投票

不确定这实际上需要窗口功能。

以下示例仅通过C12产品自行链接表和组。

CREATE TABLE sales_performance
(
 product_ID varchar(3) not null,
 sales_period varchar(4) not null,
 sales_qty char(2) not null,
 sales_index char(2) not null,
 product_sub char(3) not null,
 goal_met char(1)  not null,
 PRIMARY KEY (product_ID, sales_period)
)

INSERT INTO sales_performance
(product_ID,sales_period,sales_qty,sales_index,product_sub,goal_met) 
VALUES
 ('C12','0001','15','20','D71','Y')
,('D71','0001','07','09','C12','N')
,('F20','0001','25','30','C05','Y')
,('C05','0001','10','15','F20','N')
,('C12','0002','15','30','C05','Y')
,('C05','0002','12','06','C12','N')
,('D71','0002','30','20','F20','Y')
,('F20','0002','20','15','D71','N')
,('C12','0003','05','04','F20','N')
,('F20','0003','40','35','C12','Y')
,('D71','0003','20','20','C05','Y')
,('C05','0003','12','10','D71','N')
;

SELECT c12.*, sub.sales_index
FROM sales_performance c12
LEFT JOIN sales_performance sub 
  ON sub.sales_period < c12.sales_period 
 AND 
 (
    (sub.product_ID = c12.product_sub AND sub.goal_met = 'N') OR
    (sub.product_ID = c12.product_ID AND sub.goal_met = 'Y')
 )
WHERE c12.product_id = 'C12'
ORDER BY c12.product_ID, c12.sales_period, sub.product_ID

product_ID | sales_period | sales_qty | sales_index | product_sub | goal_met | sales_index
:--------- | :----------- | :-------- | :---------- | :---------- | :------- | :----------
C12        | 0001         | 15        | 20          | D71         | Y        | null       
C12        | 0002         | 15        | 30          | C05         | Y        | 15         
C12        | 0002         | 15        | 30          | C05         | Y        | 20         
C12        | 0003         | 05        | 04          | F20         | N        | 20         
C12        | 0003         | 05        | 04          | F20         | N        | 30         
C12        | 0003         | 05        | 04          | F20         | N        | 15         

SELECT 
 c12.*
 , ROUND(AVG(sub.sales_index),1) AS sales_index_goal
FROM sales_performance c12
LEFT JOIN sales_performance sub 
  ON sub.sales_period < c12.sales_period 
 AND 
 (
    (sub.product_ID = c12.product_sub AND sub.goal_met = 'N') OR
    (sub.product_ID = c12.product_ID AND sub.goal_met = 'Y')
 )
WHERE c12.product_id = 'C12' 
GROUP BY c12.product_ID, c12.sales_period
ORDER BY c12.product_ID, c12.sales_period;

product_ID | sales_period | sales_qty | sales_index | product_sub | goal_met | sales_index_goal
:--------- | :----------- | :-------- | :---------- | :---------- | :------- | :---------------
C12        | 0001         | 15        | 20          | D71         | Y        | null            
C12        | 0002         | 15        | 30          | C05         | Y        | 17.5            
C12        | 0003         | 05        | 04          | F20         | N        | 21.7

db <>小提琴here

2
投票

使用窗口功能是一个很好的起点。一个问题在于，您希望平均来自不同列的值，并且可能具有不同的出现次数。

我认为你需要打破计算以计算平均值：将值相加，然后将其除以出现的总和。

考虑：

SELECT *
FROM (
    SELECT 
        s.*,
        (
            0.0 + 
            COALESCE(SUM(CASE WHEN goal_met = 'Y' THEN sales_index END) OVER(
                PARTITION BY product_id 
                ORDER BY sales_period 
                ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING
            ), 0)
            + COALESCE(SUM(CASE WHEN goal_met = 'N' THEN sales_index END) OVER(
                PARTITION BY product_sub 
                ORDER BY sales_period 
                ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING
            ), 0)
        ) / (
            COALESCE(SUM(goal_met = 'Y') OVER(
                PARTITION BY product_id 
                ORDER BY sales_period 
                ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING
            ), 0)
            + COALESCE(SUM(goal_met = 'N') OVER(
                PARTITION BY product_sub 
                ORDER BY sales_period 
                ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING
            ), 0)
        ) AS sales_index_goal
    FROM sales_performance s
) x WHERE product_ID = 'C12'

在this DB fiddle中，使用您的示例数据，返回：

| product_ID | sales_period | sales_qty | sales_index | product_sub | goal_met | sales_index_goal   |
| ---------- | ------------ | --------- | ----------- | ----------- | -------- | ------------------ |
| C12        | 1            | 15        | 20          | D71         | Y        |                    |
| C12        | 2            | 15        | 30          | C05         | Y        | 20                 |
| C12        | 3            | 5         | 4           | F20         | N        | 21.666666666666668 |
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