给定两个表,sales_reps
和 sales
:
sales_reps
+--------+-------+
| rep_id | name |
+--------+-------+
| 1 | Tony |
+--------+-------+
| 2 | Jim |
+--------+-------+
| 3 | Laura |
+--------+-------+
| 4 | Sam |
+--------+-------+
sales
+------------+----------+--------+-------------+
| sale_date | sales_id | rep_id | sale_amount |
+------------+----------+--------+-------------+
| 2021-01-01 | 1 | 1 | 2000 |
+------------+----------+--------+-------------+
| 2021-01-01 | 2 | 1 | 4000 |
+------------+----------+--------+-------------+
| 2021-01-01 | 3 | 2 | 3000 |
+------------+----------+--------+-------------+
| 2021-01-01 | 4 | 1 | 1000 |
+------------+----------+--------+-------------+
| 2021-01-01 | 5 | 4 | 5000 |
+------------+----------+--------+-------------+
| 2021-01-02 | 6 | 3 | 10000 |
+------------+----------+--------+-------------+
| 2021-01-02 | 7 | 3 | 10000 |
+------------+----------+--------+-------------+
| 2021-01-02 | 8 | 2 | 4000 |
+------------+----------+--------+-------------+
| 2021-01-02 | 9 | 1 | 6000 |
+------------+----------+--------+-------------+
| 2021-01-02 | 10 | 4 | 2000 |
+------------+----------+--------+-------------+
| 2021-01-03 | 11 | 2 | 8000 |
+------------+----------+--------+-------------+
| 2021-01-03 | 12 | 2 | 1000 |
+------------+----------+--------+-------------+
| 2021-01-03 | 13 | 3 | 4500 |
+------------+----------+--------+-------------+
| 2021-01-03 | 14 | 3 | 4500 |
+------------+----------+--------+-------------+
我想显示按日期(简单)进行销售的唯一代表有多少,以及每个日期产生最高总销售额的代表的 rep_id
和 name
。如果超过一个代表在某个日期产生了相同的最大总销售额,我想显示较小的 rep_id
和该代表的 name
。结果应如下所示:
+------------+-------------+----------+----------+
| sale_date | unique_reps | best_rep | rep_name |
+------------+-------------+----------+----------+
| 2021-01-01 | 3 | 1 | Tony |
+------------+-------------+----------+----------+
| 2021-01-02 | 4 | 3 | Laura |
+------------+-------------+----------+----------+
| 2021-01-03 | 2 | 2 | Jim |
+------------+-------------+----------+----------+
劳拉和吉姆在 2021 年 1 月 3 日的销售额均为 9,000 美元。但 Jim 的 rep_id
为 2,小于 Laura 的 rep_id
为 3。因此 Jim 显示为在 2021-01-03 产生最大销售额的代表。
答案 0 :(得分:1)
Postgres 有一个 mode()
函数,但它不允许您选择哪个代表在平局的情况下选择。为此,您可以更明确:
select distinct on (s.sale_date) s.sale_date,
s.rep_id, sr.name,
count(*) over (partition by s.date) as num_reps
from sales s join
sales_reps sr
on s.rep_id = sr.rep_id
group by s.sale_date, s.rep_id
order by s.sale_date, sum(s.sale_amount) desc, s.rep_id, sr.name;
这是在做什么?它按日期和销售代表聚合。但是,由于 distinct on
,它每个日期只占用一行。在这一行:
count(*) over (partition by date)
计算代表的数量(它计算聚合后的行数)。s.rep_id
是根据 order by
条件选择的 - 首先是销售额最高,然后是最低代表 id。sr.name
是销售代表的姓名。