title: Getting the median value from the database
body: <p>A median is defined as a number separating the higher half of a data set from the lower half. Query the median of the Northern Latitudes (LAT_N) from STATION and round your answer to  decimal places.</p>
  
  <p>Input Format</p>
  
  <p>The STATION table is described as follows:</p>
  
  <pre><code>Field : Type
  ID    : NUMBER
  CITY  : VARCHAR2(21)
  STATE : VARCHAR2(2)
  LAT_N : NUMBER
  LONG_W: NUMBER
  </code></pre>
  
  <p>where LAT_N is the northern latitude and LONG_W is the western longitude.</p>
  
  <p>I could only manage to get the row index for the median value with</p>
  
  <pre><code>select floor((count(lat_n)+1)/2) from station;
  </code></pre>
  
  <p>which is row index 250. The  next step is to use this value to extract out the lat_n value at row index 250. How do I transform to SQL?</p>