Axis dimensions determine the edges of a multidimensional result set. Multidimensional Expressions (MDX) uses the SELECT clause to specify axis dimensions by assigning a set to a particular axis. The following information describes how this assignment is handled in MDX.
In the following syntax example, each
value defines one axis dimension. The number of axes in the dataset is equal to
the number of
<axis_specification> values in the
Multidimensional Expressions (MDX) query. An MDX query can support up to 128
specified axes, but very few MDX queries will use more than 5 axes.
The breakdown of the <axis_specification> syntax is:
<axis_specification> ::= <set> ON <axis_name> <axis_name> ::= COLUMNS | ROWS | PAGES | SECTIONS | CHAPTERS | AXIS(<index>)
Each axis dimension is associated with a number: 0 for the x-axis, 1 for the
y-axis, 2 for the z-axis, and so on. The
<index> value is the
axis number. For the first 5 axes, the aliases COLUMNS, ROWS, PAGES, SECTIONS,
and CHAPTERS can be used in place of AXIS(0), AXIS(1), AXIS(2), AXIS(3), and
An MDX query cannot skip axes. That is, a query that includes one or more
<axis_name> values must not exclude lower-numbered or
intermediate axes. For example, a query cannot have a ROWS axis without a
COLUMNS axis, or have COLUMNS and PAGES axes without a ROWS axis.
However, you can specify a SELECT clause with no axes (that is, an empty SELECT clause). In this case, all dimensions are slicer dimensions, and the MDX query selects one cell.
<set> value defines the contents of the axis. For
more information about sets, see Members,
Tuples, and Sets.