MDX: What is the difference of these both queries - mdx

Question

MDX: What is the difference of these queries, I'm using adventure works database.
SELECT
{[Measures].[Internet Sales Amount]} ON COLUMNS,
NON EMPTY ([Product].[Category].[Category] ,
[Date].[Calendar Year].[Calendar Year])ON ROWS
FROM [Adventure Works]
GO
SELECT
{[Measures].[Internet Sales Amount]} ON COLUMNS,
NON EMPTY ([Product].[Category].[Category] *
[Date].[Calendar Year].[Calendar Year])ON ROWS
FROM [Adventure Works]

Answer 1

Those two scripts are the same.
This is effectively putting a set of tuples on the rows - you've definied the tuple explicitly using the braces (...)
SELECT
{[Measures].[Internet Sales Amount]} ON COLUMNS
,NON EMPTY
( //<<start of tuple
[Product].[Category].[Category]
,[Date].[Calendar Year].[Calendar Year]
) ON ROWS
FROM [Adventure Works];
The second script is a cross join via the star operator *:
SELECT
{[Measures].[Internet Sales Amount]} ON COLUMNS
,NON EMPTY
[Product].[Category].[Category] * [Date].[Calendar Year].[Calendar Year] ON ROWS
FROM [Adventure Works];
When you action a crossjoin it returns a set of tuples - so you end up with the same cell set.
You could write crossjoin instead of using the star - although the star is the most used notation in modern mdx scripts:
SELECT
{[Measures].[Internet Sales Amount]} ON COLUMNS
,NON EMPTY
CrossJoin
(
[Product].[Category].[Category]
,[Date].[Calendar Year].[Calendar Year]
) ON ROWS
FROM [Adventure Works];