SQL Server PIVOT Function

2019-07-09 07:27发布

问题:

I have a query that retrieves all agents and thier modules, the result set will return 1 row per module.

SELECT
   am.agentID          AS agentid,
   pa.agentDisplayName agentdisplayname,
   m.ModuleName        ModuleName
FROM
   AgentModule AS am
   JOIN primaryagent AS pa
      ON am.agentID = pa.AgentID
   JOIN Module AS m
      ON am.ModuleID = m.ModuleID
WHERE
   m. Active = 1
   AND pa.groupID = 75

Dataset is return as below

agentid  |  agentdisplayname  |  modulename
94       |  Agent1            |  Module 1
94       |  Agent1            |  Module 2
94       |  Agent1            |  Module 3
23       |  Agent1            |  Module 2
23       |  Agent1            |  Module 3

I am trying to use the PIVOT function to return a table that looks more like

agentid  |  agentdisplayname  |  Module 1  |  Module 2  |  Module 3  |.. .. .. 
94       |  Agent1            |  1         |  1         |  1
23       |  Agent2            |  0         |  1         |  1

There are a dynamic list of modules so I cannot hard code them in the query. I have tried PICOT but it seems to expect an aggregate function and not quite sure it is what I would need for this scenario.

回答1:

You can add a extra column to you result and use min() on that column. The result will be 1 or null. Use isnull to get a 0 instead of null.

select agentid,
       agentdisplayname,
       isnull([Module 1], 0) as [Module 1],
       isnull([Module 2], 0) as [Module 2],
       isnull([Module 3], 0) as [Module 3]
from
  (
    select agentid, agentdisplayname, modulename, 1 as dummy
    from YourResultset
  ) as T
pivot
  (min(dummy) for modulename in ([Module 1],[Module 2],[Module 3])) as P

If you want to build this dynamically you need to first do a query that returns the modules you have in the result and then you need to use that to build the dynamic statement. It is probably best for you to store the result from your query in a temp table and then use that table when you build your dynamic query.

SELECT
   am.agentID          AS agentid,
   pa.agentDisplayName agentdisplayname,
   m.ModuleName        ModuleName
INTO #Tmp
FROM
   AgentModule AS am
   JOIN primaryagent AS pa
      ON am.agentID = pa.AgentID
   JOIN Module AS m
      ON am.ModuleID = m.ModuleID
WHERE
   m. Active = 1
   AND pa.groupID = 75

Build and run the dynamic query using #Tmp.

declare @FieldList1 nvarchar(max)
declare @FieldList2 nvarchar(max)
declare @SQL nvarchar(max)

set @FieldList1 =
  (select ',isnull('+quotename(modulename)+', 0) as '+quotename(modulename)
   from #Tmp
   group by modulename
   order by modulename
   for xml path(''), type).value('.', 'nvarchar(max)')

set @FieldList2 = stuff(
  (select ','+quotename(modulename)
   from #Tmp
   group by modulename
   order by modulename
   for xml path(''), type).value('.', 'nvarchar(max)') , 1, 1, '')

set @SQL = 
  'select agentid, agentdisplayname'+@FieldList1+
  'from (select agentid, agentdisplayname, modulename, 1 as dummy 
         from YourTable) as T 
   pivot (min(dummy) for modulename in ('+@FieldList2+')) as P'

exec sp_executesql @SQL

drop table #Tmp