Question

我有一个玩家游戏历史记录表，其中列出了玩家在锦标赛中玩过的所有国际象棋游戏。

CREATE TABLE [dbo].[cub_player_hist](
    [id] [int] NOT NULL,
    [player_id] [int] NULL, --Player's ID
    [Event_Title] [nvarchar](100) NULL,
    [Event_id] [int] NULL,
    [Event_Start] [smalldatetime] NULL, 
    [FullName] [nvarchar](max) NULL, -- Player's Name
    [Result_txt] [varchar](9) NULL,
    [result] [int] NULL,
    [played_id] [int] NULL, -- Opponent's ID
    [Played] [nvarchar](max) NULL, -- Opponent's Name
 CONSTRAINT [cub_player_hist_pk] PRIMARY KEY CLUSTERED 
)

我想创建一个View，它将计算每个player_id的playing_id的次数，并为每个playing_id选择最常出现的次数。

如果查看是错误的方法，那么我愿意接受建议！

Answer 1

请使用 multiple-CTE in SQL

测试以下SQL脚本

为了计算玩家所有比赛的游戏数，以及每个对手的数量，你可以使用SQL COUNT() function with Partition By clause

作为最后一步，为玩家选择最常玩的对手，我们可以使用SQL Row_Number() function with Partition By子句

;with cte as 
(
    select *,
        COUNT(*) over (partition by player_id) cnt_all,
        COUNT(*) over (partition by player_id, played_id) cnt_opp
    from [dbo].[cub_player_hist]
), cte2 as (
    select
        *, ROW_NUMBER() over (partition by player_id order by cnt_opp desc) rn
    from cte
)
select 
    player_id,
    fullname player_name,
    played_id,
    played opponent_name
from cte2 
where rn = 1
order by player_id

为每个玩家选择最常见的对手

1 个答案: