Dynamic columns not getting created in T-SQL - sql

Question

I have the following tables:
tblengineeringlookupcolumnmaster
elccolumnid | elclookupcode | elccolumnname | elcisrequired
1 | 64 | FirstName | 1
2 | 64 | LastName | 1
3 | 65 | abc | 1
4 | 65 | xyz | 1
tblengineeringlookupdetail
eldrecordId | eldlookupcode |eldlookupsequence |eldlookupvalue | eldlookupvaluedescription
245 | 64 | 0 | Red | Aravinth,Arumugam
246 | 64 | 1 | Blue | Santhosh,Chandran
247 | 64 | 2 | Green | Karthik,Balasubramanian
When I pass '64' as the parameter to the procedure.
I got the output as:
FirstName | LastName | eldRecordId
-------------------------------------
Aravinth | Arumugam | 245
Santhosh | Chandran | 246
Karthik | Balasubramanian| 247
The Store procedure used is
//SP
-- Select the columns to be used
DECLARE #tcol TABLE
(
ID INT IDENTITY(1,1)
, elclookupcode INT
, elccolumnname VARCHAR(100)
)
-- Insert the records into the table
INSERT INTO #tcol (elclookupcode, elccolumnname)
SELECT elclookupcode,elccolumnname FROM tblEngineeringLookupColumnMaster WHERE elclookupcode=#LookupCode
-- Select the columns which should be as output as a table
DECLARE #temp TABLE
(
elcLookupCode INT
, RecordId INT
, txt VARCHAR(8000)
)
-- Select the records from the table and insert
INSERT INTO #temp (elcLookupCode, RecordId, txt)
SELECT eldLookupCode,eldRecordId, eldLookupValueDescription FROM tblEngineeringLookupDetail WHERE eldLookupCode=#LookupCode
DECLARE #SQL NVARCHAR(MAX)
-- Have a table for the selected values
;WITH cte AS
(
SELECT
token = ', [' + d2.elccolumnname + '] = ''' + d.token + ''''
, d.RecordId
FROM (
SELECT
token = t.c.value('.', 'VARCHAR(50)')
, a.RecordId
, a.elcLookupCode
, rn = ROW_NUMBER() OVER (PARTITION BY a.RecordId ORDER BY a.RecordId)
FROM (
SELECT
RecordId
, elcLookupCode
, txml = CAST('<t>' + REPLACE(txt, ',', '</t><t>') + '</t>' AS XML)
FROM #temp
) a
CROSS APPLY txml.nodes('/t') t(c)
) d
-- Select the columns to be mapped
JOIN (
SELECT
elclookupcode
, elccolumnname
, rn = ROW_NUMBER() OVER (PARTITION BY elclookupcode ORDER BY elclookupcode)
FROM #tcol
) d2 ON d.elcLookupCode = d2.elclookupcode AND d2.rn = d.rn
)
-- Join all the records taken
SELECT #SQL = STUFF((
SELECT CHAR(13) + 'UNION ALL SELECT '+ STUFF((
SELECT t2.token
FROM cte t2
WHERE t2.RecordId = t.RecordId
FOR XML PATH(''), TYPE).value('.', 'VARCHAR(MAX)'), 1, 2, ''), ',[RecordId] = ' + CAST(RecordId AS VARCHAR(10))
FROM #temp t
FOR XML PATH(''), TYPE).value('.', 'VARCHAR(MAX)'), 1, 11, '')
PRINT #SQL
EXEC sp_executesql #SQL
END
The question now is:
If I pass '65' as parameter to the procedure,Where there are values in the first table(tblengineeringlookupcolumnmaster) and no corresponding values in the second table(tblengineeringlookupdetail) I'm getting no results( A message showing 3rows affected).
But I have to get the columns headers alone.
'Sample:
xyz | abc | eldrecordId
NULL |NULL | NULL
Why i'm not getting this? Where i'm wrong?

Answer 1

Try this one -
DECLARE #tcol TABLE
(
ID INT IDENTITY(1,1)
, elclookupcode INT
, elccolumnname VARCHAR(20)
)
INSERT INTO #tcol (elclookupcode, elccolumnname)
VALUES
(65, 'FirstName'),
(65, 'LastName')
DECLARE #temp TABLE
(
elcLookupCode INT
, eldRecordId INT
, txt VARCHAR(100)
)
INSERT INTO #temp (elcLookupCode, eldRecordId, txt)
VALUES
(64, 245, 'Aravinth,Arumugam'),
(64, 246, 'Santhosh,Chandran'),
(64, 247, 'Karthik,Balasubramanian')
DECLARE #SQL NVARCHAR(MAX)
;WITH cte AS
(
SELECT
token = ', [' + d2.elccolumnname + '] = ''' + d.token + ''''
, d.eldRecordId
FROM (
SELECT
token = t.c.value('.', 'VARCHAR(50)')
, a.eldRecordId
, a.elcLookupCode
, rn = ROW_NUMBER() OVER (PARTITION BY a.eldRecordId ORDER BY a.eldRecordId)
FROM (
SELECT
eldRecordId
, elcLookupCode
, txml = CAST('<t>' + REPLACE(txt, ',', '</t><t>') + '</t>' AS XML)
FROM #temp
) a
CROSS APPLY txml.nodes('/t') t(c)
) d
LEFT JOIN (
SELECT
elclookupcode
, elccolumnname
, rn = ROW_NUMBER() OVER (PARTITION BY elclookupcode ORDER BY elclookupcode)
FROM #tcol
) d2 ON d.elcLookupCode = d2.elclookupcode AND d2.rn = d.rn
)
SELECT #SQL = STUFF((
SELECT CHAR(13) + 'UNION ALL SELECT [eldRecordId] = ' + CAST(eldRecordId AS VARCHAR(10)) + ', ' +
'[elcLookupCode] = ' + CAST(elcLookupCode AS VARCHAR(10)) + ISNULL(STUFF((
SELECT t2.token
FROM cte t2
WHERE t2.eldRecordId = t.eldRecordId
FOR XML PATH(''), TYPE).value('.', 'VARCHAR(MAX)'), 1, 2, ', '), '')
FROM #temp t
FOR XML PATH(''), TYPE).value('.', 'VARCHAR(MAX)'), 1, 11, '')
PRINT #SQL
EXEC sys.sp_executesql #SQL