title: Multiple SELECT on the same field in one statement
body: <p>I got the following table:</p>
  
  <pre><code>**stats**
  
  id INT FK
  day INT    
  value INT
  </code></pre>
  
  <p>I would like to create an SQL query that will sum the values in value column in the last day, last week and last month, in one statement.</p>
  
  <p>So Far i got this:</p>
  
  <pre><code>select sum(value) from stats as A where A.day &gt; now() - 1
  union
  select sum(value) from stats as B where B.day &gt; now() - 7
  union
  select sum(value) from stats as C where C.day &gt; now() - 30
  </code></pre>
  
  <p>This returns just the first sum(value), i was expecting 3 values to return.</p>
  
  <p>Running: <code>select sum(value) from stats as A where A.day &gt; now() - X ( Where x = 1/7/30)</code> in different queries works as it should.</p>
  
  <p>What's wrong with the query? Thanks!</p>