How can I join the results of multiple pivot queries together horizontally? - sql

Question

I may not have phrased the question clearly so I'll clarify it here.
I've got a VB.NET system that displays data. To display data, I have the following SQL stored procedure that makes use of pivot:
DECLARE #cols AS NVARCHAR(MAX), #query AS NVARCHAR(MAX)
select #cols = STUFF((SELECT ',' + QUOTENAME(form_column_id) from
GetFormColumns(#formTemplateId) FOR XML PATH(''),
TYPE).value('.', 'NVARCHAR(MAX)') ,1,1,'')
set #query = N' select *
from
(select row_number as Row,fc.form_column_id, fdd.data
from
form_data_h fdh
inner join form_data_d fdd on fdd.form_data_h_id = fdh.form_data_h_id
inner join form_column fc on fc.form_column_id = fdd.form_column_id
inner join column_header c on c.column_header_id=fc.column_header_id
where fdh.is_active = 1 and fdh.form_data_h_id= ' +
CONVERT(varchar(10),#formDataHId) + ' and fc.is_active = 1
) src
pivot(
min(data)
for form_column_id in (' + #cols + N')
) piv'
execute(#query);
I had to make use of pivot because user data entry needs to be dynamic. So from this...
table results
The results now look like this.
pivot results
This data has different results filtered by particular parameters. Right now I've displayed the crop data for 2017. I want to join it with the crop data for 2018 (will change based on the Stored Procedure parameter #formDataHId).
That should result in something that looks like this...
2017 and 2018 results
Is there any way I can go about this in SQL or do I have to do that in VB.net? If so, how can I go about it?
Any ideas would be welcome because I'm a bit stumped right now. If users need to see data from let's say 2016 to 2019, it should be presented like that.

Answer 1

Pivot in SQL should be enough. If the structure of data in each year is the same, you can use UNION ALL between each year's data. Then use your query to pivot the combined years' data.
In my pivot function I use a table named Test to generate the pivot. I have 2 other tables Source2017 and Source2018. I insert both Source2017 and Source2018 using this query.
INSERT #Test
SELECT Date, Item, Quantity FROM #Source2017
UNION ALL
SELECT Date, Item, Quantity FROM #Source2018
If I only want data from 2017, I remove the Source2018 from the insert statement.
INSERT #Test
SELECT Date, Item, Quantity FROM #Source2017
Let's say I have more tables, Source2015 and Source2016. If I want to pivot all of them, just add the tables using UNION ALL.
INSERT #Test
SELECT Date, Item, Quantity FROM #Source2015
UNION ALL
SELECT Date, Item, Quantity FROM #Source2016
UNION ALL
SELECT Date, Item, Quantity FROM #Source2017
UNION ALL
SELECT Date, Item, Quantity FROM #Source2018
Full query:
IF OBJECT_ID('tempdb..#Test') IS NOT NUll DROP TABLE #Test
IF OBJECT_ID('tempdb..#Source2017') IS NOT NUll DROP TABLE #Source2017
IF OBJECT_ID('tempdb..#Source2018') IS NOT NUll DROP TABLE #Source2018
CREATE TABLE #Test
(
Date DATE,
Item VARCHAR(100),
Quantity INT
)
CREATE TABLE #Source2017
(
Date DATE,
Item VARCHAR(100),
Quantity INT
)
CREATE TABLE #Source2018
(
Date DATE,
Item VARCHAR(100),
Quantity INT
)
INSERT #Source2017 VALUES
('2017/01/01', 'Mango', 5),
('2017/01/01', 'Orange', 6),
('2017/01/02', 'Mango', 7),
('2017/01/02', 'Orange', 8),
('2017/01/02', 'Cherry', 9)
INSERT #Source2018 VALUES
('2018/01/01', 'Durian', 15),
('2018/01/02', 'Orange', 28),
('2018/01/03', 'Cherry', 19)
INSERT #Test
SELECT Date, Item, Quantity FROM #Source2017
UNION ALL
SELECT Date, Item, Quantity FROM #Source2018
DECLARE #SQL AS VARCHAR(MAX)
DECLARE #Columns AS VARCHAR(MAX)
DECLARE #Columns2 AS VARCHAR(MAX)
SELECT #Columns = COALESCE(#Columns + ',','') + QUOTENAME(Date)
FROM (SELECT DISTINCT Date FROM #Test) AS B
ORDER BY B.Date
SELECT #Columns2 = COALESCE(#Columns2 + ',','') + 'ISNULL(' + QUOTENAME(Date) + ', 0) AS [' + CAST(Date AS VARCHAR(100)) + ']'
FROM (SELECT DISTINCT Date FROM #Test) AS B
ORDER BY B.Date
SET #SQL = '
WITH PivotData AS
(
SELECT Date, Item, Quantity FROM #Test
)
SELECT
Item, ' + #Columns2 + '
FROM PivotData
PIVOT
(
SUM(Quantity)
FOR Date
IN (' + #Columns + ')
) AS PivotResult
ORDER BY Item'
EXEC(#SQL);
DROP TABLE #Test
DROP TABLE #Source2017
DROP TABLE #Source2018
Result:
+--------+------------+------------+------------+------------+------------+
| Item | 2017-01-01 | 2017-01-02 | 2018-01-01 | 2018-01-02 | 2018-01-03 |
+--------+------------+------------+------------+------------+------------+
| Cherry | 0 | 9 | 0 | 0 | 19 |
| Durian | 0 | 0 | 15 | 0 | 0 |
| Mango | 5 | 7 | 0 | 0 | 0 |
| Orange | 6 | 8 | 0 | 28 | 0 |
+--------+------------+------------+------------+------------+------------+