Hierarchy Expressions (MDX)

This section describes how to create and use hierarchy expressions in InterSystems MDX.

Details

In InterSystems MDX, a hierarchy expression has one of the following forms:

A hierarchy literal, which is a direct reference to the hierarchy as follows:
```
[dimension_name].[hierarchy_name]
```
Where:
- [dimension_name] is an MDX identifier that names a dimension.
- [hierarchy_name] is an MDX identifier that names a hierarchy within that dimension.
For example:
```
[gend].[h1]
```
A reference to a dimension:
```
[dimension_name]
```
For example:
```
[gend]
```
The system interprets this as a reference to the first visible hierarchy of that dimension.
An expression that uses an InterSystems MDX extension to refer to a hierarchy in another cube, via the following syntax:
```
[relationship_name].hierarchy_expression
```
Where relationship_name is the name of a relationship in the cube used by the query and hierarchy_expression refers to a hierarchy contained in that relationship.

Uses

A bare hierarchy expression returns all records; this expression is equivalent to an All member. (Note that you can use a bare hierarchy expression even if the dimension does not formally define an All level.) For example:

SELECT MEASURES.[%count] ON 0, colord.h1 ON 1 FROM patients
 
                             Patient Count
                                      1,000

Also, you can use a hierarchy expression as an argument to any of the following functions:

Set Expressions (MDX)

Level Expressions (MDX)