SQL - Combine multiple rows into single row with dynamic number of columns - sql

Question

I'm trying to setup a query that selects multiple rows from a table and combines similar rows into a single row with multiple columns. I believe I can do this with pivot however each row won't have the same number of columns and that's where I'm running into problems. I gave an example below of what I mean.
This:
Account Period Amount
01 0001 1111
01 0002 2222
01 0003 3333
02 0001 1111
03 0001 1111
04 0001 1111
04 0002 2222
Should be come this:
Account 0001 0002 0003
01 1111 2222 3333
02 1111
03 1111
04 1111 2222
Here is my initial query that's pulling all the data together:
WITH CTE AS(
SELECT
a.Period, a.Account, SUM(a.Amount) Amount
FROM
LedgerAP a
WHERE
a.Period >= 201500
GROUP BY a.Period, a.Account
UNION
SELECT
b.Period, b.Account, SUM(b.Amount) Amount
FROM
LedgerAR b
WHERE
b.Period >= 201500
GROUP BY b.Period, b.Account
UNION
SELECT
c.Period, c.Account, SUM(c.Amount)
FROM
LedgerEx c
WHERE
c.Period >= 201500
GROUP BY c.Period, c.Account
UNION
SELECT
d.Period, d.Account, SUM(d.Amount)
FROM
LedgerMisc d
WHERE
d.Period >= 201500
GROUP BY d.Period, d.Account
)
SELECT account,
max(case when period = #Budgetyear + '01' then SUM(amount) end) Amount1,
max(case when period = #Budgetyear + '02' then SUM(amount) end) Amount2,
max(case when period = #Budgetyear + '03' then SUM(amount) end) Amount3,
max(case when period = #Budgetyear + '04' then SUM(amount) end) Amount4,
max(case when period = #Budgetyear + '05' then SUM(amount) end) Amount5,
max(case when period = #Budgetyear + '06' then SUM(amount) end) Amount6,
max(case when period = #Budgetyear + '07' then SUM(amount) end) Amount7,
max(case when period = #Budgetyear + '08' then SUM(amount) end) Amount8,
max(case when period = #Budgetyear + '09' then SUM(amount) end) Amount9,
max(case when period = #Budgetyear + '10' then SUM(amount) end) Amount10,
max(case when period = #Budgetyear + '11' then SUM(amount) end) Amount11,
max(case when period = #Budgetyear + '12' then SUM(amount) end) Amount12
FROM CTE
GROUP BY account
ORDER BY account ASC
Now how can I go about organizing this like I have shown above? Any help would be amazing!

Answer 1

Credit to #Bluefeet's solution here, you can build up dynamic pivot something like this:
create table table1 (Account varchar(2), Period varchar(4), Amount int)
insert into table1 values
('01', '0001', 1111),
('01', '0002', 2222),
('01', '0003', 3333),
('02', '0001', 1111),
('03', '0001', 1111),
('04', '0001', 1111),
('04', '0002', 2222);
Dynamic Query:
DECLARE #cols AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX);
SET #cols = STUFF((SELECT distinct ',' + QUOTENAME(t.period)
FROM table1 t
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set #query = 'SELECT Account, ' + #cols + ' from
(
select Account
, Period
, Amount
from table1
) x
pivot
(
max(amount)
for period in (' + #cols + ')
) p '
execute(#query)
GO
Result:
+---------+------+--------+--------+
| Account | 0001 | 0002 | 0003 |
+---------+------+--------+--------+
| 01 | 1111 | 2222 | 3333 |
| 02 | 1111 | (null) | (null) |
| 03 | 1111 | (null) | (null) |
| 04 | 1111 | 2222 | (null) |
+---------+------+--------+--------+
SQL Fiddle Demo

Answer 2

Your basic pivot:
SELECT
SUM(case Period when '0001' then Amount end) as '0001',
SUM(case Period when '0002' then Amount end) as '0002',
SUM(case Period when '0003' then Amount end) as '0003'
FROM LedgerAP
GROUP BY Account
To create that query dynamically, which is helpful if you have many values for Period:
DECLARE #SQL varchar(max) = 'SELECT '
;WITH Periods AS
(
SELECT DISTINCT Period
FROM LedgerAP
)
SELECT #SQL = #SQL +
'SUM(case Period when ''' + Period + ''' then Amount end) as ''' + Period + ''','
SET #SQL = LEFT(#SQL,LEN(#SQL) - 1) + ' FROM LedgerAP GROUP BY Account'
EXEC(#SQL)