Sql pivot - but dont sum the values - sql

Question

I have a table schema that looks like this
CREATE TABLE [dbo].[Discounts](
[Id] [int] NOT NULL,
[ProductId] [varchar(50)] NOT NULL,
[LowerBoundDays] [int] NOT NULL,
[UpperBoundDays] [int] NOT NULL,
[Discount] [decimal](18, 4) NOT NULL,
And some data like this
lower upper discount(%)
product1 0 10 0
product1 10 30 1
product1 30 60 2
product1 60 90 3
product1 90 120 4
product2 0 10 0
product2 10 30 1
product2 30 60 2
product2 60 90 3
product2 90 120 4
How can I do a pivot query to get 2 rows that look like this:
0-10 10-30 30-60 60-90 90-120
product1 0 1 2 3 4
product2 0 1 2 3 4

Answer 1

Since you are using SQL Server, there are several ways that you can convert the rows of data into columns.
You can use an aggregate function with a CASE expression to get the result:
select productid,
max(case when lower = 0 and upper = 10 then discount end) [0-10],
max(case when lower = 10 and upper = 30 then discount end) [10-30],
max(case when lower = 30 and upper = 60 then discount end) [30-60],
max(case when lower = 60 and upper = 90 then discount end) [60-90],
max(case when lower = 90 and upper = 120 then discount end) [90-120]
from CorporateSpread
group by productid;
See SQL Fiddle with Demo.
If you are using SQL Server 2005+, then you can use the PIVOT function:
select productid, [0-10], [10-30], [30-60], [60-90],[90-120]
from
(
select productid,
discount,
cast(lower as varchar(10)) + '-' + cast(upper as varchar(10)) rng
from CorporateSpread
) d
pivot
(
max(discount)
for rng in ([0-10], [10-30], [30-60], [60-90],[90-120])
) piv;
See SQL Fiddle with Demo.
The above two version work great if you have a known number of values, but if you have an unknown number of ranges, then you will need to to use dynamic SQL:
DECLARE #cols AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX)
select #cols = STUFF((SELECT distinct ',' + QUOTENAME(cast(lower as varchar(10)) + '-' + cast(upper as varchar(10)))
from CorporateSpread
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set #query = 'SELECT productid, ' + #cols + '
from
(
select productid,
discount,
cast(lower as varchar(10)) + ''-'' + cast(upper as varchar(10)) rng
from CorporateSpread
) x
pivot
(
max(discount)
for rng in (' + #cols + ')
) p '
execute sp_executesql #query;
See SQL Fiddle with Demo. All versions will give a result:
| PRODUCTID | 0-10 | 10-30 | 30-60 | 60-90 | 90-120 |
-----------------------------------------------------
| product1 | 0 | 1 | 2 | 3 | 4 |
| product2 | 0 | 1 | 2 | 3 | 4 |