MDX FirstChild Function

In Multidimensional Expression, FirstChild function will return the First Child member belongs to the specified member. For example, If you know single customer name and if you want to find the Sales of a first customer then you can use this FirstChild function.

TIP: We can use MDX LastChild Function to find the Last Child Member.
MDX FirstChild Function Syntax

The basic syntax of the MDX FirstChild is:

Member_Expression.FIRSTCHILD

Member_Expression: Any Multidimensional Expression that returns valid Member.


In this article we will show you, How to write FirstChild function in MDX query with examples. For this, We are going to use the below show data

Following screenshot shows the Countries inside the Geography





Following screenshot shows the [State – Provinces] inside the France Country






MDX FirstChild Function Example

In this example we are going to find the First Children present in the France Country. It means first state present in the France country.


CODE


SELECT
[Measures].[Reseller Sales Amount] ON COLUMNS,
[Geography].[Geography].[Country].[France].FIRSTCHILD ON ROWS
FROM [Adventure Works];


OUTPUT





Analysis:

In the above MDX Query, We used [Reseller Sales amount] on the columns

[Measures].[Reseller Sales Amount] ON COLUMNS


Below line of code will write the first child member of the France from all the State-Provices present in the France country.

[Geography].[Geography].[Country].[France].FIRSTCHILD


MDX FirstChild Function Example 2


As we all know Paris is one of the state in France and our intention is to find the first state present in France then, we can use this FirstChild function. In this example we are going to find the First Children present in the State Province list and calculate the Reseller Sales Amount of that.


CODE

SELECT
[Measures].[Reseller Sales Amount] ON COLUMNS,
[Geography].[Geography].[State-Province].[Seine (Paris)].PARENT.FIRSTCHILD ON ROWS
FROM [Adventure Works];


OUTPUT





Analysis:

In the above MDX Query, We used [Reseller Sales amount] on the columns

[Measures].[Reseller Sales Amount] ON COLUMNS


From Below line of code,

[Geography].[Geography].[State-Province].[Seine (Paris)].PARENT.FIRSTCHILD


MDX will first implement the Parent function to find the parent member of a [Seine (Paris)], Which is France. Please refer MDX Parent Function for further understanding

Next, It will implement FirstChild function to find the first child member of the France Country, Which is Charente-Maritime. For Charente-Maritime State, there is no sales at all so, it is displaying Null results.

MDX FirstChild Function Alternative


In this example we are going to use the FirstChild function alternative to achieve the same result. Please refer MDX FirstSibling Function to understand the FirstSibling function.


CODE


SELECT
[Measures].[Reseller Sales Amount] ON COLUMNS,
[Geography].[Geography].[State-Province].[Seine (Paris)].FIRSTSIBLING ON ROWS
FROM [Adventure Works];


OUTPUT