creating a pivot table using sql - sql

Question

I am trying to create a pivot table in sql but am having difficulties. Here is my problem: I have a column in my database called 'statusreason', and I need to provide a sum of each statusreason for the past week. My set is as follows:
I need to pivot this table so that it appears like the following:
There are a number of statusreasons that are not represented in the above table, since they did not occur in the past week.
The query used to generate the result set is:
select inv.statusreason
, count(inv.statusreason) as 'StatusCount'
from invoicetbl inv (nolock)
inner join trucktbl tru (nolock) on inv.tru_key = tru.tru_key
where inv.client_key = 123
and inv.createdate > getdate() - 7
group by inv.statusreason
If this isn't enough information, please advise what I could add to improve the question.
Thank you for any assistance you can provide.

Answer 1

Since you want to convert your rows of data into columns, you need to PIVOT the data. This can be done a number of ways.
If you have a limited number of values that you are going to be returning, then you can use an aggregate function with a CASE expression:
select
count(case when statusreason = 181 then 1 end) [181],
count(case when statusreason = 20 then 1 end) [20],
count(case when statusreason = 212 then 1 end) [212],
count(case when statusreason = 232 then 1 end) [232]
from
(
select inv.statusreason
from invoicetbl inv (nolock)
inner join trucktbl tru (nolock)
on inv.tru_key = tru.tru_key
where inv.client_key = 123
and inv.createdate > getdate() - 7
) d;
Or you can use the PIVOT function:
select [181], [20], [212], [232]
from
(
select inv.statusreason
from invoicetbl inv (nolock)
inner join trucktbl tru (nolock)
on inv.tru_key = tru.tru_key
where inv.client_key = 123
and inv.createdate > getdate() - 7
) d
pivot
(
count(statusreason)
for statusreason in ([181], [20], [212], [232])
) p;
If you have an unknown number of values that will be returned, then you will want to look at using dynamic SQL. This creates a sql string that will then be executed.
DECLARE #cols AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX)
select #cols = STUFF((SELECT distinct ',' + QUOTENAME(statusreasons )
from statusreasontbl
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set #query = 'SELECT ' + #cols + '
from
(
select inv.statusreason
from invoicetbl inv (nolock)
inner join trucktbl tru (nolock)
on inv.tru_key = tru.tru_key
where inv.client_key = 123
and inv.createdate > getdate() - 7
) x
pivot
(
count(statusreason)
for statusreason in (' + #cols + ')
) p '
execute sp_executesql #query;