转置/将不同的行属性设置为列，并将另一个属性分组？

编程问答 2021-09-25

问题描述

您可以使用该PIVOT功能。如果您具有已知的列数，则可以对值进行硬编码：

select *
from
(
  select game, player, goals
  from yourtable
) src
pivot
(
  sum(goals)
  for player in ([John], [Paul], [Mark], [Luke])
) piv
order by game

参见带有演示的SQL Fiddle

如果列数未知，则可以使用动态sql：

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(player) 
                    from yourtable
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT game, ' + @cols + ' from 
             (
                select game, player, goals
                from yourtable
            ) x
            pivot 
            (
                sum(goals)
                for player in (' + @cols + ')
            ) p '

execute(@query)

参见带有演示的SQL Fiddle

解决方法

是否可以对下表执行查询：

Game    Player  Goals
-----   ------  ------
Game1   John    1
Game1   Paul    0
Game1   Mark    2
Game1   Luke    1
Game2   John    3
Game2   Paul    1   
Game2   Luke    1
Game3   John    0
Game3   Mark    2

结果如下：

Game    John    Paul    Mark    Luke
-----   ----    ----    ----    ----
Game1   1       0       2       1
Game2   3       1       -       1
Game3   0       -       2       -

它将每个不同的玩家变成一列，并将游戏分组，从而为每个玩家每个游戏提供目标。

sqlsql