Teradata CASE和COUNT語法錯誤

Question

尋找如何編寫CASE和COUNT查詢的方法，以按日期顯示從2/1/2017-4/19/2017之間的商品銷售總天數。 我收到的單詞“ DATES”和“ BETWEEN”之間有“預期的區別”。

表格1：

ITEM    SALE    DATES
Apple   Yes   4/19/2017
Apple   Yes   2/18/2017
Apple   Yes   1/17/2017
Apple   no    3/16/2017
Apple   no    4/17/2017
Banana  Yes   4/19/2017
Banana  Yes   2/18/2017
Banana  Yes   1/17/2017
Banana  Yes   3/16/2017
Banana  no    4/17/2017

我在尋找什么：

ITEM    Total days on sale
Apple          2
Banana         3

當前查詢：

SELECT
    ITEM,
    CASE WHEN SALE='YES' THEN COUNT(DATES BETWEEN '2/1/2017' AND '4/19/2017') END AS TOTAL_DAYS_ON_SALE_DAYS
FROM TABLE 1
GROUP BY 
    ITEM
ORDER BY 
    ITEM ASC

Answer 1

我認為您需要條件聚合：

SELECT ITEM,
       SUM(CASE WHEN SALE = 'YES' AND DATES BETWEEN DATE '2017-02-01' AND DATE '2017-04-19'
                THEN 1 ELSE 0
           END) AS TOTAL_DAYS_ON_SALE_DAYS
FROM TABLE 1
GROUP BY ITEM
ORDER BY ITEM ASC;

Answer 2

您可以僅將DATES上的該檢查移至WHERE子句。
求和

SELECT
ITEM,
SUM(CASE 
WHEN SALE = 'Yes' 
THEN 1 
ELSE 0 
END) AS TOTAL_DAYS_ON_SALE_DAYS
FROM TABLE 1
WHERE DATES BETWEEN '2/1/2017' AND '4/19/2017'
 GROUP BY ITEM
 ORDER BY ITEM ASC

您查詢的問題是，可以使用COUNT（DATES）之類的東西，但不能使用BETWEEN或=之類的條件。