How to SQL PIVOT on two columns and with dynamic column names? - sql-server

Question

I have a key value pair set of rows to associate to a unique identifier (ApplicationId).
The data would look something like this:
| ApplicationId | Key | Value | Date |
| 123 | A | abc | 2020-3-1 14:00:01.000 |
| 123 | B | abd | 2020-3-1 14:00:02.000 |
| 123 | C | abe | 2020-3-1 14:00:03.000 |
| 124 | A | abf | 2020-3-1 14:01:00.000 |
| 124 | D | abg | 2020-3-1 14:01:01.000 |
The end result i'm looking for would be this:
| ApplicationId | A | A_Date | B | B_Date | C | C_Date | D | D_Date |
| 123 | abc | 2020-3-1 14:00:01.000 | abd | 2020-3-1 14:00:02.000 | abe | 2020-3-1 14:00:03.000 | NULL | NULL |
| 124 | abf | 2020-3-1 14:01:00.000 | NULL | NULL | NULL | NULL | abg | 2020-3-1 14:01:01.000 |
The Keys A,B,C,D are unknown so hard coding the column names isn't possible.
Here is something that works with one PIVOT
IF OBJECT_ID('tempdb.dbo.#_BLAH') IS NOT NULL DROP TABLE #_BLAH
SELECT et.[ApplicationId] et.[Key], et.[Value], et.[Date]
INTO #_BLAH
FROM ExampleTbl et
WHERE et.[Date] > DATEADD(dd, -1, GetDate())
DECLARE #_cols AS NVARCHAR(MAX)
DECLARE #_sql AS NVARCHAR(MAX)
SELECT
#_cols += QUOTENAME([Key]) + ','
FROM
#_BLAH
GROUP BY
[Key];
SET #_cols = STUFF((SELECT ',' + QUOTENAME(T.[Key])
FROM #_BLAH AS T
GROUP BY T.[Key]
FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'),1,1,'')
set #_sql = 'SELECT [ApplicationId], ' + #_cols + '
FROM ( SELECT * FROM #_BLAH) AS SRC
PIVOT ( MAX([Value]) FOR [Key] IN (' + #_cols + ') ) AS p';
EXEC(#_sql)
I've so far been unable to find an example or an article attempting to make a second dynamic column and adding in the value that relates the specific Key in my example.
My SQL above will accomplish creating the row i want except for the #_Date column i need.

Answer 1

Try this:
DROP TABLE IF EXISTS #DataSource;
DROP TABLE IF EXISTS #DataSourcePrepared;
CREATE TABLE #DataSource
(
[ApplicationId] INT
,[Key] CHAR(1)
,[Value] VARCHAR(12)
,[Date] DATETIME2(0)
);
INSERT INTO #DataSource ([ApplicationId], [Key], [Value], [Date])
VALUES (123, 'A', 'abc', '2020-3-1 14:00:01.000')
,(123, 'B', 'abd', '2020-3-1 14:00:02.000')
,(123, 'C', 'abe', '2020-3-1 14:00:03.000')
,(124, 'A', 'abf', '2020-3-1 14:01:00.000')
,(124, 'D', 'abg', '2020-3-1 14:01:01.000');
CREATE TABLE #DataSourcePrepared
(
[ApplicationId] INT
,[ColumnName] VARCHAR(32)
,[Value] VARCHAR(32)
)
INSERT INTO #DataSourcePrepared ([ApplicationId], [ColumnName], [Value])
SELECT [ApplicationId]
,[Key]
,[value]
FROM #DataSource
UNION ALL
SELECT [ApplicationId]
,[Key] + '_Date'
,CONVERT(VARCHAR(19), [Date], 121)
FROM #DataSource;
DECLARE #DymanimcTSQLSatement NVARCHAR(MAX)
,#DynamicColumns NVARCHAR(MAX);
SET #DynamicColumns = STUFF
(
(
SELECT ',' + QUOTENAME([ColumnName])
FROM #DataSourcePrepared
GROUP BY [ColumnName]
ORDER BY [ColumnName]
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1
,1
,''
);
SET #DymanimcTSQLSatement = N'
SELECT *
FROM #DataSourcePrepared
PIVOT
(
MAX([value]) FOR [ColumnName] IN (' + #DynamicColumns +')
) PVT;';
EXECUTE sp_executesql #DymanimcTSQLSatement;
You just need to prepare the data before the actual PIVOT. Also, note that I am ordering the columns when I am building the dynamic part by name. In your real case, you may want to change this to something complex.

Answer 2

you can try this
DECLARE #_cols AS NVARCHAR(MAX) =''
DECLARE #_sql AS NVARCHAR(MAX)
SELECT
#_cols +=','+ QUOTENAME([Key]) + ',' + QUOTENAME([Key]+'_Date')
FROM
(SELECT DISTINCT [Key] FROM ExampleTbl) T
SET #_cols = STUFF(#_cols,1,1,'')
set #_sql = 'SELECT * FROM (
SELECT ApplicationId, [Key], Value FROM ExampleTbl
UNION ALL
SELECT ApplicationId, [Key] + ''_Date'' AS [Key], CONVERT(VARCHAR(30), [Date],121 ) AS Value FROM ExampleTbl
) SRC
PIVOT (MAX(Value) FOR [Key] IN ('+#_cols +' )) AS PVT';
EXEC(#_sql)
Result:
ApplicationId A A_Date B B_Date C C_Date D D_Date
------------- ------- --------------------------- ---------- -------------------------- ------------ ------------------------- ------- -------------------------
123 abc 2020-03-01 14:00:01.000 abd 2020-03-01 14:00:02.000 abe 2020-03-01 14:00:03.000 NULL NULL
124 abf 2020-03-01 14:01:00.000 NULL NULL NULL NULL abg 2020-03-01 14:01:01.000