Grouping results by test - sql-server

Question

I have a table with this structure:
Test Value Shape
1 1,89 20
1 2,08 27
1 2,05 12
2 2,01 12
2 2,05 35
2 2,03 24
I need a column for each Test value, in this case, something like this:
Test 1 | Test 2
Value | Shape | Value | Shape
I tried to do this with pivot, but the results wasn't good. Can someone help me?
[]'s

Answer 1

There are a few different ways that you can get the result since you are using SQL Server. In order to get the result, you will first need to create a unique value that will allow you return multiple rows for each Test. I would apply a windowing function like row_number():
select test, value, shape,
row_number() over(partition by test
order by value) seq
from yourtable
This query will be used as the base for the rest of your process. This creates a unique sequence for each test and then when you apply the aggregate function you are able to return multiple rows.
You can get your final result using an aggregate function with a CASE expression:
select
max(case when test = 1 then value end) test1Value,
max(case when test = 1 then shape end) test1Shape,
max(case when test = 2 then value end) test2Value,
max(case when test = 2 then shape end) test2Shape
from
(
select test, value, shape,
row_number() over(partition by test
order by value) seq
from yourtable
) d
group by seq;
See SQL Fiddle with Demo.
If you want to implement the PIVOT function, then I would first need to unpivot your multiple columns of Value and Shape and then apply the PIVOT. You will still use row_number() to generate a unique sequence that will be needed to return multiple rows. The basic syntax will be:
;with cte as
(
-- get unique sequence
select test, value, shape,
row_number() over(partition by test
order by value) seq
from yourtable
)
select test1Value, test1Shape,
test2Value, test2Shape
from
(
-- unpivot the multiple columns
select t.seq,
col = 'test'+cast(test as varchar(10))
+ col,
val
from cte t
cross apply
(
select 'value', value union all
select 'shape', cast(shape as varchar(10))
) c (col, val)
) d
pivot
(
max(val)
for col in (test1Value, test1Shape,
test2Value, test2Shape)
) piv;
See SQL Fiddle with Demo. Both versions give a result:
| TEST1VALUE | TEST1SHAPE | TEST2VALUE | TEST2SHAPE |
|------------|------------|------------|------------|
| 1,89 | 20 | 2,01 | 12 |
| 2,05 | 12 | 2,03 | 24 |
| 2,08 | 27 | 2,05 | 35 |