### The .NextMember Function

The **.NextMember **function, according to the *Analysis Services Books Online*, "returns the next member in the level that contains a specified member." In other words, the function returns the member in the dimensional hierarchy occurring *later* at the same level as the specified member. The **.NextMember** function works in a manner similar to the **.PrevMember** function, except that, instead of returning the member that occurs at the same level as the specified member, *earlier* in the hierarchy, it returns the same-level member that *follows* the specified member within the hierarchy.

*Discussion:*

The utility of the **.NextMember** function is intuitive for purposes of meeting business needs that include the example we have discussed earlier, the determination of change over a given pair of periods (next year over the current year, and so forth).

*Syntax*

Let's look at an example to familiarize ourselves with the syntax.

WITH
MEMBER [Measures].[Warehouse Margin] AS
'[Measures].[Warehouse Sales] - [Measures].[Warehouse Cost]'
SELECT
{([Time].CurrentMember),([Time].NextMember)} ON COLUMNS,
{([Warehouse].[Country].USA)} ON ROWS
FROM Warehouse
WHERE ([Measures].[Warehouse Margin])

The result dataset returned would appear as shown in **Illustration 6** below:

Illustration 6: Example Result Dataset Using the .NextMember Function

The **.NextMember** function is used within the definition of the calculated member, inside the **WITH** clause. In this case, we are specifying the *next member* of the **Time** dimension at the year level, which turns out to be *1998*, because, unlike in previous examples, we have specified no slicer in the **WHERE** clause. The result is that the *current member* for the year is the *default*, *1997*. Therefore, the "next" member of the time dimension at the same hierarchical level is *1998*. We note that the results we obtain appear consistent with those obtained in previous queries, from slightly different approaches.

*Practice*

Let's practice with the **.NextMember** function, combining its use with that of the **.CurrentMember** function, in a manner that assists us in performing analysis of performance from one year to the next, just as we have done before. We return to the **MDX Sample Application**, creating a new query for the purposes of this exercise.

12. **Select File -****->**** New** from the top menu of the **MDX Sample Application**.

13. Type the following query into the **Query** pane:

-- MDX08-3: Tutorial Query No. 3
WITH
MEMBER [Measures].[Margin Base Year] AS
'([Time].CurrentMember , [Measures].[Warehouse Sales])-([Time].CurrentMember,
[Measures].[Warehouse Cost])'
MEMBER [Measures].[Margin Base + 1] AS
'([Time].NextMember , [Measures].[Warehouse Sales])-([Time].NextMember,
[Measures].[Warehouse Cost])'
MEMBER [Measures].[$ Change] AS
'([Time].CurrentMember , [Measures].[Margin Base + 1]) - ([Time].CurrentMember,
[Measures].[Margin Base Year])'
SELECT
{ [Measures].[Margin Base Year], [Measures].[Margin Base + 1], [Measures].[$ Change]} ON
COLUMNS,
{([Warehouse].[Country].[USA])} ON ROWS
FROM Warehouse

14. Select key **F5** from the top menu to execute the query.

The query runs and the result dataset appears, as shown in **Illustration 7**.

Illustration 7: The Query Result Dataset

The query delivers the results as requested; we see the three related calculated measures, **Margin Base Year**, **Margin Base + 1**, and **$ Change**; the latter, **$ Change**, is again a calculated measure that is made up of the subtraction of one of the first two calculated measures from the other.

We see that the behavior of the **.NextMember** function is, therefore, very similar to that of the **.PrevMember** function, only it acts, conceptually, "in the opposite direction." We can also readily see the potential usefulness of the function with regard to its capability to support the analysis of measures that change over time, among other uses within our data sources.

### Next in Our Series ...

In this lesson, we began an overview of additional "relative" member functions, expanding upon our earlier exposure to the powerful **.Members** function, and extending our exploration to the **.CurrentMember**, **.PrevMember** and **.NextMember** functions. We introduced **calculated members** briefly, as an avenue to demonstrating the use of the "relative" member functions. As we noted in the *Calculated Members* section above, we will take up calculated members in far more detail as the series progresses; I hope that our initial exposure to them in this article, and our recurring use of them going forward to achieve various objectives, will make their characteristics and uses familiar as we progress in the series.

In our next lessons, we will introduce the **time series functions** group. As we discussed in this lesson, many business requirements revolve around the** **performance of analysis within the context of time. We saw simple approaches to meeting examples of these requirements by using the** CurrentMember**, **.PrevMember** and **.NextMember** functions** **in this lesson, mainly because the time dimension provides an intuitive way to demonstrate many functions such as these.

Because of pervasive business needs to analyze data within the context of time, MDX provides a specialized group of time series functions to meet these needs. In the next lesson, we will overview the **PeriodsToDate()** function, then we will discuss the specialized "shortcut" functions that are based upon it, including the **YTD()**, **QTD()**, **MTD()**, and **WTD()**. In subsequent lessons, we will explore other time series functions and expressions, together with other capabilities of MDX to help us to meet typical business needs.

**»** See All Articles by Columnist **William E. Pearson, III**

Discuss this article in the MSSQL Server 2000 Analysis Services and MDX Topics Forum.