Grouping in SSRS 2008 - Filtering - ssrs-2008

Question

I'm new to SSRS. I want to group a transactions table by customerid and count how many transactions per customerid. I was able to do that.
But then I want to sort by that count, and/or filter by that count. How do you that?
Thanks!

Answer 1

To set up sorting and filtering on row groups, right click on the row group.
You can access the Group Sorting and Filtering properties here. They should both allow you to set up rules based on the name of your count column.

Answer 2

Option 1
If you have no need to show the transactions in the report then the aggregation should be performed at the database level in the query, not by SSRS. You'll get the benefits of:
Faster rendering.
You'll be sending less data over the network.
There'll be less data for the SSRS engine to process, therefore any ordering can be performed quicker.
Your data set can be 'pre-ordered' by putting the most common/expected values in the ORDER BY clause of the underlying query.
Thereby giving any rendering a speed boost, also.
Any filters can be applied directly against the aggregated data returned by the query without having to try and do complex expressions in SSRS.
This will also give a performance boost when rendering.
You could have a "filter" parameter that could be used in the HAVING clause of an aggregate query
Again, a performance boost due to less data across the network, and to be processed.
Gives a level of interactivity to your reports as opposed to trying to pre-define user tastes and having filter conditions set on expressions or a 'best-guess'.
Example
-- Will filter out any customers who have 2 or fewer transactions
DECLARE #Filter AS int = 2
;
SELECT
CustomerId
,COUNT(TransactionId)
FROM
Transactions
GROUP BY
CustomerId
HAVING
COUNT(TransactionId) > #Filter
Option 2
If you still need to show the transactions, then add an additional column to your query that performs the Count() using the OVER clause and PARTITION BY customerid, like so:
COUNT(transactions) OVER (PARTITION BY customerid) AS CustomerTransactionCount
Assuming a very simple table structure you'll end up with a query structure like so:
SELECT
CustomerId
,TransactionId
,TransactionAttribute_1
,TransactionAttribute_2
,TransactionAttribute_3
.
.
.
,TransactionAttribute_n
,COUNT(TransactionId) OVER (PARTITION BY CustomerId) AS CustomerTransactionCount
FROM
Transactions
You'll be able to use CustomerTransactionCount as a filter and sorting column in any row/column groups within SSRS.
Drawback of this approach
Window functions, i.e. using the OVER (PARTITION BY...) cannot be used in HAVING clauses as no GROUP BY clause is used. This means any filtering will have to be carried out by SSRS.
Workaround options
We take the query above and wrap a CTE around it. This will allow us to filter based on the aggregate results.
Put the aggregate in a derived table.
CTE Example
--Filter variable
DECLARE #Filter AS int = 2
;
WITH DataSet_CTE AS
(
-- Build the data set with transaction information and the aggregate column
SELECT
CustomerId
,TransactionId
,TransactionAttribute_1
,TransactionAttribute_2
,TransactionAttribute_3
.
.
.
,TransactionAttribute_n
,COUNT(TransactionId) OVER (PARTITION BY CustomerId) AS CustomerTransationCount
FROM
Transactions
)
-- Filter and return data
SELECT *
FROM DataSet_CTE
WHERE CustomerTransationCount > #Filter
Derived Table Example
--Filter variable
DECLARE #Filter AS int = 2
;
SELECT
*
FROM
(
-- Build the data set with transaction information and the aggregate column
SELECT
CustomerId
,TransactionId
,TransactionAttribute_1
,TransactionAttribute_2
,TransactionAttribute_3
.
.
.
,TransactionAttribute_n
,COUNT(TransactionId) OVER (PARTITION BY CustomerId) AS CustomerTransationCount
FROM
Transactions
) AS DataSet
WHERE
DataSet.CustomerTransationCount > #Filter