SQL：将 ISNULL 与动态枢轴结合使用

Question

我想让枢轴产生的所有 NULL 值都变成 0。我已经将 ISNULL 放置在每个可以想象到的地方，但似乎没有任何效果。枢轴与 ISNULL 兼容吗？代码如下：

    DECLARE @startDate datetime
    SET @startDate = '2013-01-01'

    DECLARE @sql varchar(MAX)
    SET @sql = 'SELECT 
    CLIENTNAME, PROJECTNAME, RESOURCE, [' +
      REPLACE(SUBSTRING(CONVERT(varchar, @startDate, 13), 4, 8), ' ', '') + '], [' +
      REPLACE(SUBSTRING(CONVERT(varchar, DATEADD(MONTH, 1, @startDate), 13), 4, 8), ' ', '') + '], [' +
      REPLACE(SUBSTRING(CONVERT(varchar, DATEADD(MONTH, 2, @startDate), 13), 4, 8), ' ', '') + '], [' +
      REPLACE(SUBSTRING(CONVERT(varchar, DATEADD(MONTH, 3, @startDate), 13), 4, 8), ' ', '') + '], [' +
      REPLACE(SUBSTRING(CONVERT(varchar, DATEADD(MONTH, 4, @startDate), 13), 4, 8), ' ', '') + '], [' +
      REPLACE(SUBSTRING(CONVERT(varchar, DATEADD(MONTH, 5, @startDate), 13), 4, 8), ' ', '') + ']
    FROM
      (
      SELECT
        CLIENTNAME, PROJECTNAME, RESOURCE, FORECASTTOTAL
      FROM viewprojscheduling_group
      ) AS SourceTable
    PIVOT
      (
      SUM(FORECASTTOTAL)
      FOR SCHEDULEDDATE IN (' +
              QUOTENAME(REPLACE(SUBSTRING(CONVERT(varchar, @startDate, 13), 4, 8), ' ', '')) + ', ' +
              QUOTENAME(REPLACE(SUBSTRING(CONVERT(varchar, DATEADD(MONTH, 1, @startDate), 13), 4, 8), ' ', '')) + ', ' +
              QUOTENAME(REPLACE(SUBSTRING(CONVERT(varchar, DATEADD(MONTH, 2, @startDate), 13), 4, 8), ' ', '')) + ', ' +
              QUOTENAME(REPLACE(SUBSTRING(CONVERT(varchar, DATEADD(MONTH, 3, @startDate), 13), 4, 8), ' ', '')) + ', ' +
              QUOTENAME(REPLACE(SUBSTRING(CONVERT(varchar, DATEADD(MONTH, 4, @startDate), 13), 4, 8), ' ', '')) + ', ' +
              QUOTENAME(REPLACE(SUBSTRING(CONVERT(varchar, DATEADD(MONTH, 5, @startDate), 13), 4, 8), ' ', '')) + ')
      ) AS PivotTable'

    execute(@sql)

Answer 1

我会将您的查询设置得略有不同，因为虽然它是动态的，因为列名称正在变化，但您仍然对列数进行了硬编码。

首先，我将使用递归 CTE 生成您想要创建的月/年列表。

DECLARE @startDate datetime

SET @startDate = '2013-01-01'

;with dates as
(
  select @startdate datelist, 1 sp
  union all
  select dateadd(month, 1, datelist), sp+1
  from dates
  where sp+1 <= 5 -- change this number 5 to the number of months you need
)
select   sp,
  REPLACE(SUBSTRING(CONVERT(varchar(11), datelist, 13), 4, 8), ' ', '') MONTHANDYEAR
from dates

请参阅SQL Fiddle 演示。这将自动创建包含年份的 5 个月的列表。那么您就不会硬编码这 5 列。您当前的查询不够灵活。如果您需要 12 个月，您将不得不更改代码，会发生什么情况。

生成日期列表后，我会将其插入临时表中，以便您可以使用它来获取列。

获取列列表的代码是：

select @cols = STUFF((SELECT ',' + QUOTENAME(monthandyear) 
                    from #datesTemp
                    group by monthandyear, sp
                    order by sp
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

select @colNames = STUFF((SELECT  ', isnull(' + QUOTENAME(monthandyear)+', 0) as '+QUOTENAME(monthandyear)
                    from #datesTemp
                    group by monthandyear, sp
                    order by sp
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

请参阅SQL Fiddle 演示。你会看到有两个版本。第一个@cols获取将在pivot. 第二个@colNames将在最终列表中用于用零SELECT替换值。null

然后你把它们放在一起，代码将是：（注意：我使用的是你上一个问题的答案的一个版本）

DECLARE @cols AS NVARCHAR(MAX),
    @colNames AS NVARCHAR(MAX),
    @query AS NVARCHAR(MAX),
    @startDate datetime

SET @startDate = '2013-01-01'

;with dates as
(
  select @startdate datelist, 1 sp
  union all
  select dateadd(month, 1, datelist), sp+1
  from dates
  where sp+1 <= 5 -- change this number 5 to the number of months you need
)
select   sp,
  REPLACE(SUBSTRING(CONVERT(varchar(11), datelist, 13), 4, 8), ' ', '') MONTHANDYEAR
into #datesTemp
from dates

select @cols = STUFF((SELECT ',' + QUOTENAME(monthandyear) 
                    from #datesTemp
                    group by monthandyear, sp
                    order by sp
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

select @colNames = STUFF((SELECT  ', isnull(' + QUOTENAME(monthandyear)+', 0) as '+QUOTENAME(monthandyear)
                    from #datesTemp
                    group by monthandyear, sp
                    order by sp
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')


set @query = 'SELECT resource, clientname,' + @colNames + ' 
             from 
             (
                select [CLIENTNAME], [RESOURCE], [FORECASTTOTAL],
                   REPLACE(SUBSTRING(CONVERT(varchar(11), SCHEDULEDDATE, 13), 4, 8), '' '', '''') monthandyear
                from viewprojscheduling_group
            ) x
            pivot 
            (
                sum(FORECASTTOTAL)
                for monthandyear in (' + @cols + ')
            ) p '

execute(@query)

请参阅SQL Fiddle 演示。此查询将为您提供结果：

| RESOURCE | CLIENTNAME | JAN2013 | FEB2013 | MAR2013 | APR2013 | MAY2013 |
---------------------------------------------------------------------------
|     res1 |        abc |    1000 |    2000 |       0 |       0 |       0 |
|     res1 |        def |       0 |       0 |    2000 |       0 |       0 |
|     res2 |        def |    1500 |       0 |       0 |       0 |       0 |
|     res3 |        ghi |       0 |       0 |    2500 |       0 |       0 |