CASE 声明未提供所需答案

Question

我有一个非常大的表格，其中显示了产品和事件类型的每日记录。我愿意重新安排下面查询的编写方式，但认为 case 语句将为我提供必要的输出。

表_1：

DATES      PRODUCT  EVENT
5/20/2017   APPLE   SALE
5/21/2017   APPLE   SALE
5/22/2017   APPLE   SALE
5/23/2017   APPLE   SALE
5/24/2017   APPLE   SALE
5/25/2017   APPLE   SALE
5/26/2017   APPLE   SALE
5/27/2017   APPLE   FULL PRICE
5/28/2017   APPLE   FULL PRICE
5/29/2017   APPLE   FULL PRICE
5/30/2017   APPLE   FULL PRICE
5/31/2017   APPLE   FULL PRICE
6/1/2017    APPLE   FULL PRICE
6/2/2017    APPLE   FULL PRICE
6/3/2017    APPLE   FULL PRICE
6/4/2017    APPLE   FULL PRICE
6/5/2017    APPLE   FULL PRICE
6/6/2017    APPLE   FULL PRICE
6/7/2017    APPLE   LIQUIDATION
6/8/2017    APPLE   LIQUIDATION
6/9/2017    APPLE   LIQUIDATION
6/10/2017   APPLE   LIQUIDATION
6/11/2017   APPLE   LIQUIDATION
6/12/2017   APPLE   LIQUIDATION
6/13/2017   APPLE   LIQUIDATION
6/14/2017   APPLE   LIQUIDATION
5/20/2017   BANANA  SALE
5/21/2017   BANANA  SALE
5/22/2017   BANANA  SALE
5/23/2017   BANANA  SALE
5/24/2017   BANANA  SALE
5/25/2017   BANANA  SALE
5/26/2017   BANANA  SALE
5/27/2017   BANANA  SALE
5/28/2017   BANANA  SALE
5/29/2017   BANANA  SALE
5/30/2017   BANANA  FULL PRICE
5/31/2017   BANANA  FULL PRICE
6/1/2017    BANANA  FULL PRICE
6/2/2017    BANANA  FULL PRICE
6/3/2017    BANANA  FULL PRICE
6/4/2017    BANANA  FULL PRICE
6/5/2017    BANANA  FULL PRICE
6/6/2017    BANANA  FULL PRICE
6/7/2017    BANANA  FULL PRICE
6/8/2017    BANANA  FULL PRICE
6/9/2017    BANANA  FULL PRICE
6/10/2017   BANANA  FULL PRICE
6/11/2017   BANANA  FULL PRICE
6/12/2017   BANANA  FULL PRICE
6/13/2017   BANANA  FULL PRICE
6/14/2017   BANANA  FULL PRICE

当前查询：

select
    product,
    case when event in ('liquidation') then 'yes' else 'no' end LIQ,
    count(dates) as days
FROM TABLE_1
where dates between '5/20/2017' and '6/14/2017'
group by
    product

我想要一个按产品分类的记录，如果它在日期范围内处于清算状态，是/否。此查询执行，但给出以下结果：

PRODUCT   LIQ         DAYS
APPLE     NO           18
APPLE     YES           8
BANANA    NO           26

如果产品在 2017 年 5 月 20 日至 2017 年 6 月 14 日之间清算，我正在寻找一个简单的“是”或“否”。这是我正在寻找的内容：

PRODUCT    LIQ        DAYS
APPLE      YES         26
BANANA     NO          26

谢谢！

Answer 1

下面使用“yes”和“no”的属性即“yes”>“no”：

select product,
       max(case when event in ('liquidation') then 'yes' else 'no' end) as LIQ,
       count(dates) as days
from TABLE_1
where dates between '2017-05-20' and '2017-06-14'
group by product;