将 IF EXISTS 应用于 XQuery 的结果

Question

我有一个 XQuery，用于检查 SQL Server 2008 R2 维护计划中是否存在重建索引任务。

如何将IF EXISTS 包裹起来，或者使用.exist XQuery 方法？我只想根据是否找到行从该查询中获取布尔值。

 ;WITH XMLNAMESPACES 
    (
        'www.microsoft.com/SqlServer/Dts' AS DTS
       ,'www.microsoft.com/SqlServer/Dts/Tasks' AS SQLTask)


    SELECT
      Nodes.node.value('(@DTS:ExecutableType)[1]', 'varchar(200)') AS ExecutableType,
      Nodes.node.value('(DTS:Property[@DTS:Name="ObjectName"])[1]', 'varchar(50)') AS ObjectName
    FROM
      (
        SELECT 
             CAST(CAST([packagedata] as varbinary(max)) as xml) PackageDataXml
        FROM [msdb].[dbo].[sysmaintplan_subplans] sub
          JOIN msdb.dbo.sysssispackages pack on sub.plan_id = pack.id
          JOIN msdb.dbo.sysssispackagefolders fold on pack.folderid = fold.folderid 
          JOIN msdb.dbo.sysjobs jobs on sub.job_id = jobs.job_id
          JOIN msdb.dbo.sysjobschedules jsched on jobs.job_id = jsched.job_id 
          JOIN msdb.dbo.sysschedules sched on jsched.schedule_id = sched.schedule_id 
          WHERE pack.packagetype = 6
          AND jobs.enabled = 1
          AND sched.enabled = 1
          AND (CAST(YEAR(GETDATE()) AS bigint) * 100 + MONTH(GETDATE())) * 100 + DAY(GETDATE()) BETWEEN sched.active_start_date AND active_end_date
          AND (CAST(DATEPART(HOUR,GETDATE()) AS bigint) * 100 + DATEPART(MINUTE,GETDATE())) * 100 + DATEPART(SECOND,GETDATE()) BETWEEN sched.active_start_time AND active_end_time
      ) SysPackages
      CROSS APPLY 
        SysPackages.PackageDataXml.nodes('/DTS:Executable/DTS:Executable/DTS:Executable') Nodes(Node)
    WHERE
      Nodes.node.value('@DTS:ExecutableType', 'varchar(200)') 
        LIKE 'Microsoft.SqlServer.Management.DatabaseMaintenance.DbMaintenanceReindexTask%';

（以上查询是another SO question的结果。）

Answer 1

我找不到直接在 XQuery 语句中执行 IF EXISTS() 的方法。

但是，可以将 XQuery 的结果插入到临时表中，然后根据临时表的内容执行IF EXISTS()。

IF OBJECT_ID('tempdb..#PlanResults') IS NOT NULL 
    DROP TABLE #PlanResults;

CREATE TABLE #PlanResults (
    ExecutableType varchar(200),
    ObjectName varchar(50)
)

;WITH XMLNAMESPACES 
    (
        'www.microsoft.com/SqlServer/Dts' AS DTS
       ,'www.microsoft.com/SqlServer/Dts/Tasks' AS SQLTask)

    INSERT INTO #PlanResults

    SELECT
      Nodes.node.value('(@DTS:ExecutableType)[1]', 'varchar(200)') AS ExecutableType,
      Nodes.node.value('(DTS:Property[@DTS:Name="ObjectName"])[1]', 'varchar(50)') AS ObjectName
    FROM
      (
        SELECT 
             CAST(CAST([packagedata] as varbinary(max)) as xml) PackageDataXml
        FROM [msdb].[dbo].[sysmaintplan_subplans] sub
          JOIN msdb.dbo.sysssispackages pack on sub.plan_id = pack.id
          JOIN msdb.dbo.sysssispackagefolders fold on pack.folderid = fold.folderid 
          JOIN msdb.dbo.sysjobs jobs on sub.job_id = jobs.job_id
          JOIN msdb.dbo.sysjobschedules jsched on jobs.job_id = jsched.job_id 
          JOIN msdb.dbo.sysschedules sched on jsched.schedule_id = sched.schedule_id 
          WHERE pack.packagetype = 6
          AND jobs.enabled = 1
          AND sched.enabled = 1
          AND (CAST(YEAR(GETDATE()) AS bigint) * 100 + MONTH(GETDATE())) * 100 + DAY(GETDATE()) BETWEEN sched.active_start_date AND active_end_date
          AND (CAST(DATEPART(HOUR,GETDATE()) AS bigint) * 100 + DATEPART(MINUTE,GETDATE())) * 100 + DATEPART(SECOND,GETDATE()) BETWEEN sched.active_start_time AND active_end_time
      ) SysPackages
      CROSS APPLY 
        SysPackages.PackageDataXml.nodes('/DTS:Executable/DTS:Executable/DTS:Executable') Nodes(Node)
    WHERE
      Nodes.node.value('@DTS:ExecutableType', 'varchar(200)') LIKE 'Microsoft.SqlServer.Management.DatabaseMaintenance.DbMaintenanceReindexTask%';

IF EXISTS (SELECT ObjectName FROM #PlanResults)
BEGIN
    PRINT 'Take action here.'
END

IF OBJECT_ID('tempdb..#PlanResults') IS NOT NULL 
    DROP TABLE #PlanResults;