Question

这是我的数据：

CREATE TABLE SALES (
    ts TIMESTAMP NOT NULL,
    name VARCHAR(50) NOT NULL,
    quantity INTEGER,
    price DECIMAL(2,2)
);

INSERT INTO SALES VALUES
    ("2017-02-08 13:38:02", "apple", 6, 4.38),
    ("2017-02-08 13:38:02", "banana", 10, 3.50),
    ("2017-02-08 13:38:02", "orange", 8, 2.98),
    ("2017-02-08 09:21:52", "banana", 6, 2.67),
    ("2017-02-08 09:21:52", "pear", 3, 2.00),
    ("2017-02-07 15:21:32", "apple", 6, 4.38),
    ("2017-02-07 15:21:32", "banana", 6, 2.67),
    ("2017-02-07 11:03:16", "orange", 8, 2.98),
    ("2017-02-07 11:03:16", "banana", 4, 1.17);

我想获得今天但不是昨天销售的商品。

我可以使用以下方法将它们分为两列：

select
    name,
    SUM(case when strftime('%Y-%m-%d', sales_ts) = '2017-02-08' then quantity  else 0 end) as today,
    SUM(case when strftime('%Y-%m-%d', sales_ts) = '2017-02-07' then quantity  else 0 end) as yday
from sales
group by name
having yday = 0

结果：

| name | today | yday
---------------------
| pear |   3   |  0

但我怎么能得到2列，1为名称，1为名为＃34; sold_today_but_not_yday＆＃34;有真/假值吗？那可能吗？（最好不使用子查询）。

Answer 1

您可以使用case：

select name,
       (case when SUM(case when strftime('%Y-%m-%d', sales_ts) = '2017-02-08' then quantity  else 0 end) > 0 and
                  SUM(case when strftime('%Y-%m-%d', sales_ts) = '2017-02-07' then quantity  else 0 end) = 0
             then 1 else 0
        end) as isTodayNotYesterday
from sales
group by name;

我可以将此销售比较纳入一个列吗？

1 个答案: