Procedure: Use the IS Operator to Perform Comparisons
within the FILTER() Function
The
report authors / developers have an additional request which we can help them
to meet with the IS operator. This time, they wish to use the Filter()
function within a query which will allow them to focus upon Internet Sales
at a specific geographical level. While our colleagues have asked that we craft
the query to return the Internet Sales measure for customers within a
single U. S. state, Georgia, for Fiscal Year 2004, we confirm
their understanding that, given the core query, the capability to perform ad hoc
queries, where the information consumer is prompted at runtime for a state or
states (or members at other geographic levels, for that matter) becomes a simple
matter of parameterizing the unique name for the state, etc., within the Filter()
function we will place within the rows-axis specification of the query. Because
we have demonstrated to the developers, that parameterization of this sort
becomes easily attainable within Reporting Services, assuming that
sufficiently sophisticated queries are put into place to support it (within
either the Reporting Services or Analysis Services layers), the
core query is deemed valuable to the team.
Having obtained consensus on the proposed target dataset, we
are ready to begin constructing the query.
4.
Select File
--> New from the main menu.
5.
Select Query
with Current Connection from the cascading menu that appears next, as
depicted in Illustration 11.
Illustration 11: Create a New Query with the Current
Connection ...
A new tab, with a
connection to the Adventure Works cube (we can see it listed in the
selector of the Metadata pane, once again) appears in the Query
pane.
6.
Type (or cut and paste) the
following query into the Query pane:
-- MDX045-002-1 IS Operator within a Filter() Function
SELECT
{[Measures].[Internet Sales Amount]} ON AXIS(0),
{FILTER (
[Customer].[Customer Geography].MEMBERS,
[Customer].[Customer Geography].CURRENTMEMBER.PARENT
IS [Customer].[Customer Geography].[State-Province].[Georgia]
)
} ON AXIS(1)
FROM
[Adventure Works]
WHERE
([Date].[Fiscal].[Fiscal Year].[FY 2004])
The Query pane appears, with our input, as shown in Illustration
12.
Illustration 12: Our Initial Query in the Query Pane ...
7.
Execute the
query by clicking the Execute button in the toolbar, as before.
The Results pane is, once again, populated by
Analysis Services. This time, the dataset depicted in Illustration
12 appears.
Illustration 13: Results Dataset –The Filtered Dataset is
Returned ...
In the returned dataset, we see that the query appears to
deliver the intended results: only those members of Customer Geography
whose parent is the State-Province of Georgia (the cities
of Georgia) are displayed.
8.
Select File
-> Save MDXQuery2.mdx As ..., name the file MDX045-002-1.mdx,
and place it in the same location used to store the earlier queries.
The
effect, as we see, has been to filter the results dataset to return only those
members that "pass" the conditional test enacted by the IS operator
within the Filter() function. That is, only those members who return a
"true" are included within the final results.
The
client representatives inform us that their immediate goals have been met, and
that the examples we have shared have illustrated the principles of operation
behind IS operator. We discuss related matters, such as
parameterization within Reporting Services, and make an appointment to
return to the client site at a future date to demonstrate the concepts.
9.
Select File
-> Exit to leave the SQL Server Management Studio, when ready.
Summary ...
In
this article, we shifted our examination from the MDX functions, as we
have upon occasion in the past, to concentrate upon an operator. We
introduced the IS operator, noting that, like other logical operators,
it evaluates values and returns a Boolean value. We explained that the IS operator's
utility lies in its capability to perform comparisons between objects within Analysis
Services.
After
discussing the straightforward purpose of the IS operator, to
ascertain the equivalence of two object expressions, we examined the manner
in which IS manages to do this, and ways we can leverage the operator to
perform efficient comparisons to meet various business needs in our own
environments. Next, we examined the syntax with which we employ IS.
Finally, we undertook illustrative examples whereby we put the IS operator
to work, both within the definition of a calculated member and, in conjunction
with the MDX Filter() function, within an axis specification of a SELECT
statement, to gain some hands-on practice in its use. Throughout our
practice session, we briefly discussed the results datasets we obtained
from each of the queries we constructed.
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