按变量按行计数

Question

我有以下查询 -

SELECT
  P.PRODUCT_NUMBER, 
  P.PRODUCT_DESCRIPTION, 
  SUM(S.NET_AMOUNT), 
  ROUND(STDDEV(S.NET_AMOUNT),2) AS STD_DEV  
--(SELECT COUNT OF NET_AMOUNT < = 1$ FROM PFI_FACT_SALES GROUPED BY THE SAME P.PRODUCT_NUMBER) AS CNT
    FROM PFI_DIM_PRODUCT P
    JOIN PFI_FACT_SALES S
    ON P.PRODUCT_PK_ID = S.PRODUCT_PK_ID
    WHERE P.PRODUCT_NUMBER = 'ABC'
      GROUP BY P.PRODUCT_NUMBER, P.PRODUCT_DESCRIPTION;

这是我想不通的部分 -

(SELECT COUNT OF NET_AMOUNT < = 1$ FROM PFI_FACT_SALES GROUPED BY THE SAME P.PRODUCT_NUMBER) AS CNT

按产品编号和产品描述获取必要的行级数据组的最佳方法是什么？

谢谢。

Answer 1

一种方法是使用相关子查询：

SELECT P.PRODUCT_NUMBER, P.PRODUCT_DESCRIPTION, SUM(S.NET_AMOUNT), 
       ROUND(STDDEV(S.NET_AMOUNT), 2) AS STD_DEV  ,
       (SELECT COUNT(*)
        FROM PFI_FACT_SALES s2
        WHERE s2.PRODUCT_PK_ID = s.PRODUCT_PK_ID AND
              NET_AMOUNT <= 1
       ) as CNT
FROM PFI_DIM_PRODUCT P JOIN
     PFI_FACT_SALES S
     ON P.PRODUCT_PK_ID = S.PRODUCT_PK_ID
WHERE P.PRODUCT_NUMBER = 'ABC'
GROUP BY P.PRODUCT_NUMBER, P.PRODUCT_DESCRIPTION;

我很确定您也可以使用条件窗口求和来做到这一点：

SELECT P.PRODUCT_NUMBER, P.PRODUCT_DESCRIPTION, SUM(S.NET_AMOUNT), 
       ROUND(STDDEV(S.NET_AMOUNT), 2) AS STD_DEV,
       SUM(CASE WHEN NET_AMOUNT <= 1 THEN 1 ELSE 0 END) OVER (PARTITION BY s.PRODUCT_PK_ID) as CNT
FROM PFI_DIM_PRODUCT P JOIN
     PFI_FACT_SALES S
     ON P.PRODUCT_PK_ID = S.PRODUCT_PK_ID
WHERE P.PRODUCT_NUMBER = 'ABC'
GROUP BY P.PRODUCT_NUMBER, P.PRODUCT_DESCRIPTION;

按变量按行计数

Row-wise count group by variables

sql

oracle

oracle-sqldeveloper