title: MDX aggregation and where clause fundamentals
body: <p>I have this very simple query:</p>
  
  <pre><code>select [Measures].[MyMeasure]  on 0,
  [MyDimension].[MyHierarchy].[MyMember] on 1
  from MyCube
  </code></pre>
  
  <p>and I am getting a number in the intersection (for example <code>1500</code>).</p>
  
  <p>Then, I wrote the same query a little bit different:</p>
  
  <pre><code>select [MyDimension].[MyHierarchy].[MyMember]  on 0
  from MyCube
  where [Measures].[MyMeasure]
  </code></pre>
  
  <p>And I still get 1500.</p>
  
  <p>But when I change a query like this:</p>
  
  <pre><code>select [Measures].[MyMeasure]  on 0
  from MyCube
  where [MyDimension].[MyHierarchy].[MyMember] 
  </code></pre>
  
  <p>The result of the query is empty.</p>
  
  <p>But I do not understand why, since as I understand, the context of the cell is the same, or not?</p>
  
  <p>When I run this query:</p>
  
  <pre><code>with member measures.test as [MyDimension].[MyHierarchy].currentmember.name 
  select {[Measures].[MyMeasure],measures.test} on 0 from MyCube where 
  [MyDimension].[MyHierarchy].[MyMember] 
  </code></pre>
  
  <p>For <code>MyMeasure</code> result is empty, and for test measure result is <code>MyMember</code>.</p>