Can a Pivot table be used with a unknown number of columns? - sql

Question

If I have a team table with a unknown amount of members, is there a way to make the pivot query dynamic?
create table #t (
team varchar (20), member varchar (20)
)
insert into #t values ('ERP', 'Jack')
insert into #t values ('ERP', 'John')
insert into #t values ('ERP', 'Mary')
insert into #t values ('ERP', 'Tim')
insert into #t values ('CRM', 'Robert')
insert into #t values ('CRM', 'Diana')
select * from #t
select team, [1] as teamMember1, /* 1st select */
[2] as teamMember2, [3] as teamMember3
from
(select team , member, row_number () /* 3rd select */
over (partition by team order by team) as rownum
from #t) a
pivot (max(member) for rownum in ([1], [2], [3])) as pvt
drop table #t

Answer 1

Why yes, yes there is. Here's a script I cooked up years ago for a similar problem that was ultimately solved by giving the user Excel and washing my hands of it. I apologize it's not configured with your example data, but hopefully it's easy to follow.
Hope that helps,
John
--------------START QUERY--------------
-- Example Table
CREATE TABLE #glbTestTable
(
ProviderID INT,
Total INT,
PaymentDate SMALLDATETIME
)
--So the dates insert properly
SET DATEFORMAT dmy
-- Populate Example Table
INSERT INTO #glbTestTable VALUES (232, 12200, '12/01/09')
INSERT INTO #glbTestTable VALUES (456, 10200, '12/01/09')
INSERT INTO #glbTestTable VALUES (563, 11899, '02/03/09')
INSERT INTO #glbTestTable VALUES (221, 5239, '13/04/09')
INSERT INTO #glbTestTable VALUES (987, 7899, '02/03/09')
INSERT INTO #glbTestTable VALUES (1, 1234, '02/08/09')
INSERT INTO #glbTestTable VALUES (2, 4321, '02/07/09')
INSERT INTO #glbTestTable VALUES (3, 5555, '02/06/09')
-- Raw Output
SELECT *
FROM #glbTestTable
-- Build Query for Pivot --
DECLARE #pvtColumns VARCHAR(MAX)
SET #pvtColumns = ''
-- Grab up to the first 1023 "Columns" that we want to use in Pivot Table.
-- Tables can only have 1024 columns at a maximum
SELECT TOP 1023 #pvtColumns = #pvtColumns + '[' + CONVERT(VARCHAR, PaymentDate, 103) + '], '
FROM (SELECT DISTINCT PaymentDate FROM #glbTestTable) t_distFP
-- Create PivotTable Query
DECLARE #myQuery VARCHAR(MAX)
SET #myQuery = '
SELECT ProviderID, ' + LEFT(#pvtColumns, LEN(#pvtColumns) - 1) + '
FROM (SELECT ProviderID, PaymentDate, Total
FROM #glbTestTable) AS SourceTable
PIVOT
(
SUM(Total)
FOR PaymentDate IN (' + LEFT(#pvtColumns, LEN(#pvtColumns) - 1) + ')
) AS PivotTable'
-- Run the Pivot Query
EXEC(#myQuery)
-- Cleanup
DROP TABLE #glbTestTable
---------------END QUERY---------------