根据组统计删除记录组

【问题标题】：Delete Group of Records based on Group Statistic根据组统计删除记录组
【发布时间】：2021-10-07 09:30:27
【问题描述】：

我有以下两个示例表

团队

Team ID	Team Name
1	Bears
2	Tigers
3	Lions
4	Sharks

玩家

Player ID	Name	Team ID	Playtime
1	John	1	5
2	Adam	1	4
3	Smith	1	5
4	Michelle	2	5
5	Stephanie	2	10
6	David	2	10
7	Courtney	2	2
8	Frank	2	7
9	Teresa	2	1
10	Michael	3	3
11	May	4	1
12	Daniel	4	1
13	Lisa	4	4

我需要一个符合以下条件的 select 语句

选择所有少于 4 人的球队
计算出这些球队中所有球员的总上场时间，并以此为基础对结果表进行降序排序

根据给出的示例，我想要一个如下所示的表格：

团队

Team Name	Num Players	Total Playtime
Bears	3	14
Sharks	3	6
Lions	1	3

最后，我想从前一个表中删除所有偶数行，所以最终表看起来像：

Team Name	Num Players	Total Playtime
Bears	3	14
Lions	1	3

【问题讨论】：

标签： sql postgresql

【解决方案1】：

您可以尝试以下方法：

查询 #1

SELECT
    t."Team Name",
    COUNT(p."Player ID") as "Num Players",
    SUM(p."Playtime") as "Total Playtime"
FROM
    teams t
LEFT JOIN
    players p ON t."Team ID"=p."Team ID"
GROUP BY
    t."Team Name"
HAVING
    COUNT(p."Player ID") < 4
ORDER BY 
    SUM(p."Playtime") DESC;

Team Name	Num Players	Total Playtime
Bears	3	14
Sharks	3	6
Lions	1	3

查询 #2

SELECT
    t1."Team Name",
    t1."Num Players",
    t1."Total Playtime"
FROM (
SELECT
    ROW_NUMBER() OVER (ORDER BY SUM(p."Playtime") DESC) as rn,
    t."Team Name",
    COUNT(p."Player ID") as "Num Players",
    SUM(p."Playtime") as "Total Playtime"
FROM
    teams t
LEFT JOIN
    players p ON t."Team ID"=p."Team ID"
GROUP BY
    t."Team Name"
HAVING
    COUNT(p."Player ID") < 4
) t1
WHERE MOD(rn,2)=1
ORDER BY rn;

Team Name	Num Players	Total Playtime
Bears	3	14
Lions	1	3

View on DB Fiddle

让我知道这是否适合你。

【讨论】：

成功了，谢谢！