SQL Server：引用如何在 for 循环中动态创建列？

Question

我认为我遇到了引用问题。我要换

  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_2Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 2 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_3Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 3 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_4Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 4 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_5Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 5 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_6Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 6 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_7Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 7 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_8Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 8 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_9Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 9 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_10Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 10 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_11Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 11 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_12Mp'
  ,CAST(REPLACE([NET_VALUE_1M],',','.') as float)/SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS BETWEEN 12 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_13Mp'

有一个while循环

SELECT

      CAST(REPLACE([NET_VALUE_1M],',','.') as float)
      /
     SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) 
         OVER (PARTITION BY [ID] ORDER BY [CMONTH] 
            ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) as 'NET_VALUE_1M_PROP_2Mp'


      DECLARE @cnt INT =2;
      DECLARE @cnt_total INT =12;

      WHILE @cnt < @cnt_total 
      BEGIN
        DECLARE @SQL NVARCHAR(MAX);
        SET @SQL =',CAST(REPLACE([NET_VALUE_1M],',','.') as float)
             /
          SUM(CAST(REPLACE([NET_VALUE_1M],',','.') as float)) 
                 OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS 
                   BETWEEN @cnt PRECEDING AND CURRENT ROW) 
                       as ['NET_VALUE_1M_PROP_']+@cnt+['Mp']'
      EXECUTE(@SQL)

        SET @cnt=@cnt+1;
      END;


  FROM [Channel_AGG]

导致错误：

消息 102，第 15 级，状态 1，第 13 行
',' 附近的语法不正确。

消息 156，第 15 级，状态 1，第 20 行
关键字“FROM”附近的语法不正确。

引用如何声明 SQL 命令？我尝试了[' 开场报价和'] 结束报价，如此处所示How to create/add columns using a variable in a loop，但错误仍在继续。那么在 SQL Server 2014 的 for 循环中创建初始命令？

Answer 1

我不确定您要做什么，或者您在尝试执行不完整的代码片段时期望发生什么，但是您的引用问题可以通过对字符串中的每个单引号使用两个单引号来解决.例如：

 ',CAST(REPLACE([NET_VALUE_1M],'','',''.'') as float)
             /
          SUM(CAST(REPLACE([NET_VALUE_1M],'','',''.'') as float)) 
                 OVER (PARTITION BY [ID] ORDER BY [CMONTH] ROWS 
                   BETWEEN '+convert(nvarchar(10),@cnt-1)+' PRECEDING AND CURRENT ROW) 
                       as [NET_VALUE_1M_PROP_'+convert(nvarchar(10),@cnt)+'Mp]'

您还需要在连接之前将@cnt 转换为字符类型。

你应该在你的循环之外声明你的@sql，并且可能是连接的（例如@sql =+ ...或@sql = @sql + ...）而不是重置循环内的值。

与其盲目尝试exec(@sql)，不如看看你正在使用print @sql 或select @sql 创建什么。