用不同的列制作表格并分配值以将它们相加

【问题标题】：Make table out of different columns and assign values to add them up用不同的列制作表格并分配值以将它们相加
【发布时间】：2022-01-09 22:43:11
【问题描述】：

我想要这个：

Winner_R | Winner_PV | Loser_PV
---------|-----------|----------
Team_A   | NULL      | NULL
---------|-----------|----------
NULL     | Team_B    | Team_C
---------|-----------|----------
Team_C   | NULL      | NULL

其中获胜等于 3 分，PV 获胜等于 2 分，PV 失败等于 1 分，

这样显示：

Team   | Points
-------|-------
Team_A | 3
-------|-------
Team_B | 2
-------|-------
Team_C | 4

我只是不知道如何将值与 SQL 语句连接起来！任何帮助表示赞赏:)

【问题讨论】：

标签： sql database

【解决方案1】：

你可以这样做：

select team, sum(points) as points
from (
  select winner_r as team, count(*) * 3 as points from t group by winner_r
  union all select winner_pv, count(*) * 2 from t group by winner_pv
  union all select loser_pv, count(*) from t group by loser_pv
) x
where team is not null
group by team

或者，您可以先过滤掉行并在最后聚合，如下所示：

select team, sum(points) as points
from (
  select winner_r as team, 3 as points from t where winner_r is not null
  union all select winner_pv, 2 from t where winner_pv is not null
  union all select loser_pv, 1 from t where loser_pv is not null
) x
group by team

【讨论】：

您可能需要在子查询后添加where x.team is not null 以删除空团队行。
@Austin Goot catch.
@TheImpaler 谢谢！