How to pivot a table to a view on matching-length delimited cells - tsql

Question

Disclaimer: I'm dealing with a rather old legacy system so any comments telling me about poor design are redundant, although I do genuinely appreciate any such sentiment. There is a new version that solves most legacy problems but we still have to maintain the old system, so basically, we have to manage for now.
I have a table that looks like this (yes, that is a single column, I know):
And I need a view (for reporting purposes) that will dynamically process the data in said table and return this:
The values are \n-delimited (shudder) and you can assume there will always be the same number of values in each cell (9 in the example, although other databases could have 4 or 12 or any number), although I suppose having NULL-insertion in the event of missing values couldn't hurt. They will also always be in a matching order (as in the example, 'AUD', 'Australian Dollar', and '$' are all the first values in their respective cells, and so on).
I've found various approaches to splitting a single cell out into a view, but nothing that covers merging data in such a way as I require. Sitting at home with a cold has not helped my research capabilities. Help me StackOverflow, you're my only hope!
Bonus points for tidy, relatively readable SQL examples, although I'm anticipating messiness as a natural by-product of the hackish nature of my required solution.

Answer 1

Something like this. I didn't take the time to build out the tables, but it should be fairly obvious where you can replace my variables with your rows. You will also want to do a replace char(10) where I have used commas. You could package it up in a table valued function and then call as a view.
declare #xml1 xml
declare #xml2 xml
declare #xml3 xml
declare #c1 nvarchar(250)
declare #c2 nvarchar(250)
declare #c3 nvarchar(250)
set #c1 = N'AUD,CAD,EUR,GBP,JPY,NZD,USD,KES,CHF';
set #c2 = N'Australian Dollar,Canadian Dollar,Euro,Pound Sterling,Yen,New Zealand Dollar,United States Dollar,Kenyan Shilling, Swiss Franc';
set #c3 = N'$,$,C,L,Y,$,$,K,F';
-- you'd use replace(#c1, char(10), '</r><r>') etc etc for /n delimited code
set #xml1 = N'<root><r>' + replace(#c1,',','</r><r>') + '</r></root>';
set #xml2 = N'<root><r>' + replace(#c2,',','</r><r>') + '</r></root>';
set #xml3 = N'<root><r>' + replace(#c3,',','</r><r>') + '</r></root>';
select code.code, name.name, symbol.symbol
from
(select ROW_NUMBER() over (order by ##rowcount) as ck,
c.value('.','varchar(max)') as [code]
from #xml1.nodes('//root/r') as a(c)) as code
inner join
(select ROW_NUMBER() over (order by ##rowcount) as nk,
n.value('.','varchar(max)') as [name]
from #xml2.nodes('//root/r') as a(n)) as name on code.ck = name.nk
inner join
(select ROW_NUMBER() over (order by ##rowcount) as sk,
s.value('.','varchar(max)') as [symbol]
from #xml3.nodes('//root/r') as a(s)) as symbol on symbol.sk = name.nk
You can run this as a single script in SSMS for verification that it works. No schema necessary.

Answer 2

Using Jeff Moden's Tally Ho! CSV splitter:
CREATE FUNCTION [dbo].[DelimitedSplit8K]
--===== Define I/O parameters
(#pString VARCHAR(8000), #pDelimiter CHAR(1))
--WARNING!!! DO NOT USE MAX DATA-TYPES HERE! IT WILL KILL PERFORMANCE!
RETURNS TABLE WITH SCHEMABINDING AS
RETURN
--===== "Inline" CTE Driven "Tally Table" produces values from 1 up to 10,000...
-- enough to cover VARCHAR(8000)
WITH
E1(N) AS (
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1
), --10E+1 or 10 rows
E2(N) AS (SELECT 1 FROM E1 a, E1 b), --10E+2 or 100 rows
E4(N) AS (SELECT 1 FROM E2 a, E2 b), --10E+4 or 10,000 rows max
cteTally(N) AS (--==== This provides the "base" CTE and limits the number of rows right up front
-- for both a performance gain and prevention of accidental "overruns"
SELECT TOP (ISNULL(DATALENGTH(#pString),0)) ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E4
),
cteStart(N1) AS (--==== This returns N+1 (starting position of each "element" just once for each delimiter)
SELECT 1 UNION ALL
SELECT t.N+1 FROM cteTally t WHERE SUBSTRING(#pString,t.N,1) = #pDelimiter
),
cteLen(N1,L1) AS(--==== Return start and length (for use in substring)
SELECT s.N1,
ISNULL(NULLIF(CHARINDEX(#pDelimiter,#pString,s.N1),0)-s.N1,8000)
FROM cteStart s
)
--===== Do the actual split. The ISNULL/NULLIF combo handles the length for the final element when no delimiter is found.
SELECT ItemNumber = ROW_NUMBER() OVER(ORDER BY l.N1),
Item = SUBSTRING(#pString, l.N1, l.L1)
FROM cteLen l
;
and inline CTE data like this
with
data as (select Num,Currencies from (values
(1,'AUD'+char(10)+'CAD'+char(10)+'USD'+char(10)+'KES')
,(2,'Australian DOllar'+char(10)+'Canadian Dollar'+char(10)+'US Dollar'+char(10)+'Kenyan Shilling')
,(3,'$'+char(10)+'$'+char(10)+'$'+char(10)+'k')
)data(Num,Currencies)
),
The solution is as simple as this:
map as (select * from (values
(1,'Code')
,(2,'Name')
,(3,'Symbol')
)map(Num,Col )
)
select
ItemNumber
,max(Code) as Code
,max(Name) as Name
,max(Symbol) as Symbol
from (
select
map.Num
,map.Col
,c.Item
,c.ItemNumber
from data
join map
on map.Num = data.Num
cross apply dbo.DelimitedSplit8K(data.Currencies,char(10)) c
) t
pivot (max(Item) for Col in (Code,Name,Symbol)) pvt
group by ItemNumber
to give us:
ItemNumber Code Name Symbol
-------------- ---- -------------------- ---------------
1 AUD Australian DOllar $
2 CAD Canadian Dollar $
3 USD US Dollar $
4 KES Kenyan Shilling k

Answer 3

Hope this Helps. Run all together or replace the table variable with a temptable.
Sample Data:
IF OBJECT_ID(N'tempdb..#table') > 0
BEGIN
DROP TABLE #table
END
DECLARE #table TABLE(ATTRIBUTELVAUE VARCHAR(MAX))
INSERT INTO #table
SELECT
'AFN
ALL
DZD
USD
EUR
AOA
XCD
XCD
ARS'
INSERT INTO #table
SELECT
'Afghanistan
Albania
Algeria
American Samoa
Andorra
Angola
Anguilla
Antigua and Barbuda
Argentina'
INSERT INTO #table
SELECT
'AF
AL
DZ
AS
AD
AO
AI
AG
AR'
Query:
IF OBJECT_ID(N'tempdb..#TEMP') > 0
BEGIN
DROP TABLE #TEMP
END
DECLARE #StartLoop INT
DECLARE #EndLoop INT
DECLARE #Code TABLE (ID INT IDENTITY(1, 1),
Code VARCHAR(250))
DECLARE #Name TABLE (ID INT IDENTITY(1, 1),
Name VARCHAR(250))
DECLARE #Symbol TABLE (ID INT IDENTITY(1, 1),
Symbol VARCHAR(250))
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS ID,
*
INTO #Temp
FROM #table
SELECT #StartLoop = MIN(ID),
#EndLoop = MAX(ID)
FROM #Temp
WHILE #StartLoop <= #EndLoop
BEGIN
DECLARE #WorkingString VARCHAR(MAX)
SELECT #WorkingString = ATTRIBUTELVAUE + CHAR(10) + ' '
FROM #Temp
WHERE ID = #StartLoop
--print #WorkingString
WHILE CHARINDEX(CHAR(10), #WorkingString) > 0
BEGIN
DECLARE #SearchCharacter INT
DECLARE #WorkingStringLength INT
DECLARE #TempStringLength INT
DECLARE #TempString VARCHAR(MAX)
SET #WorkingStringLength = LEN(#WorkingString)
SET #SearchCharacter = CHARINDEX(CHAR(10), #WorkingString)
SET #TempString = SUBSTRING(#WorkingString, 1, #SearchCharacter - 1)
SET #TempStringLength = LEN(#TempString)
SET #WorkingString = SUBSTRING(#WorkingString, #SearchCharacter + 1, #WorkingStringLength)
SET #TempString = REPLACE(#TempString, CHAR(13), '')
IF #StartLoop = 1
BEGIN
INSERT INTO #Code
SELECT #TempString
END
IF #StartLoop = 2
BEGIN
INSERT INTO #Name
SELECT #TempString
END
IF #StartLoop = 3
BEGIN
INSERT INTO #Symbol
SELECT #TempString
END
END
SET #StartLoop = #StartLoop + 1
END
SELECT Code,
Name,
Symbol
FROM #Code AS c
JOIN #Name AS n
ON c.ID = n.ID
JOIN #Symbol AS s
ON s.ID = n.ID
Cleanup:
IF OBJECT_ID(N'tempdb..#TEMP') > 0
BEGIN
DROP TABLE #TEMP
END
IF OBJECT_ID(N'tempdb..#table') > 0
BEGIN
DROP TABLE #table
END

Answer 4

Because I needed a view, this ended up being my solution:
CREATE FUNCTION [dbo].[CurrencyTableGenerator]()
RETURNS
#CurrencyTable TABLE(
Code NVARCHAR(250)
,Name NVARCHAR(250)
,Symbol NVARCHAR(250)
)
AS
BEGIN
DECLARE #xml1 XML
DECLARE #xml2 XML
DECLARE #xml3 XML
DECLARE #C1 NVARCHAR(250)
DECLARE #C2 NVARCHAR(250)
DECLARE #c3 NVARCHAR(250)
SET #c1 = (SELECT ...)
SET #c2 = (SELECT ...)
SET #c3 = (SELECT ...)
SET #xml1 = N'<root><r>' + REPLACE(#c1, CHAR(10), '</r><r>') + '</r></root>';
SET #xml2 = N'<root><r>' + REPLACE(#c2, CHAR(10), '</r><r>') + '</r></root>';
SET #xml3 = N'<root><r>' + REPLACE(#c3, CHAR(10), '</r><r>') + '</r></root>';
INSERT INTO #CurrencyTable
SELECT Code.Code, Name.Name, Symbol.Symbol
FROM
(SELECT ROW_NUMBER() OVER (ORDER BY ##ROWCOUNT) AS ck,
c.value('.', 'VARCHAR(250)') AS [Code]
FROM #xml1.nodes('//root/r') AS a(c)) AS Code
INNER JOIN
(SELECT ROW_NUMBER() OVER (ORDER BY ##ROWCOUNT) AS nk,
n.value('.', 'VARCHAR(250)') AS [Name]
FROM #xml2.nodes('//root/r') AS a(n)) AS Name ON Code.ck = Name.nk
INNER JOIN
(SELECT ROW_NUMBER() OVER (ORDER BY ##ROWCOUNT) AS sk,
s.value('.', 'VARCHAR(250)') AS [Symbol]
FROM #xml3.nodes('//root/r') AS a(s)) AS Symbol ON Symbol.sk = Name.nk
RETURN
END
GO
CREATE VIEW [dbo].[CurrencyView]
AS
SELECT * FROM [dbo].[CurrencyTableGenerator]()
GO
Thanks to RThomas for the function.