使用变量命名列

Question

我想计算一系列游戏中所有玩家的升分差异。我希望第一列名称 PD1 具有最少的点差，PD2 次之，依此类推。我希望使用一个变量来执行此操作，该变量仅根据游戏数量将整数添加到 'PD' 的末尾。当我将 AS @ColumnName 添加到计算的末尾时，我不断收到错误消息。

USE [Rugby Pools]


DECLARE @counter int
DECLARE @MaxPlayer int
DECLARE @ColumnName varchar(50)

SET @counter = (SELECT MIN([Player_ID]) FROM [dbo].[Players])
SET @MaxPlayer = (SELECT MAX([Player_ID]) FROM [dbo].[Players])


DECLARE @gamecounter int
DECLARE @MaxGame int
SET @gamecounter = (SELECT MIN([Game_ID]) FROM [dbo].[Match])
SET @MaxGame = (SELECT MAX([Game_ID]) FROM [dbo].[Match])
SET @ColumnName='PD'+@gamecounter

WHILE @gamecounter <= @MaxGame

BEGIN


WHILE @counter <= @MaxPlayer

BEGIN



SELECT     TOP (@gamecounter)   dbo.Players.Player_ID, dbo.Entries.Game_ID, ABS(ABS(dbo.Entries.Home_Score-dbo.Entries.Away_Score)-(dbo.Match.Home_Score-dbo.Match.Away_Score)) AS @ColumnName
FROM            Entries INNER JOIN
                         Match ON Entries.Game_ID = Match.Game_ID INNER JOIN
                         Players ON Entries.Player_ID = Players.Player_ID

                         WHERE dbo.Match.Home_Score IS NOT NULL AND dbo.Players.Player_ID=@counter

                         ORDER BY Players.Player_ID, PointsDiff1 ASC

SET @Counter += 1

                         END                        

SET @gamecounter += 1

END

一旦开始工作，我将能够对其进行更改以更新 table，这将使我能够提供一个联盟 table 由获胜决定的球员，然后是整个课程的最佳分差比赛的。

Answer 1

像这样将最终查询部分更改为动态 sql。只有动态sql.

才能实现

 declare @query nvarchar(max)
 set @query = ' SELECT TOP (' + cast(@gamecounter as varchar(10)) + ') dbo.Players.Player_ID, 
               dbo.Entries.Game_ID, ABS(ABS(dbo.Entries.Home_Score-dbo.Entries.Away_Score)-(dbo.Match.Home_Score-dbo.Match.Away_Score)) AS ' + QUOTENAME(@ColumnName) + '
    FROM            Entries INNER JOIN
                             Match ON Entries.Game_ID = Match.Game_ID INNER JOIN
                             Players ON Entries.Player_ID = Players.Player_ID

                             WHERE dbo.Match.Home_Score IS NOT NULL AND dbo.Players.Player_ID= ' + cast(@counter as varchar(10)) + '
                             ORDER BY Players.Player_ID, PointsDiff1 ASC'

  sp_executesql @query

使用变量命名列

Naming a Column using Variable

tsql

sql-server

variables

columnname