Difference between revisions of "Aggregates with DISTINCT"

Latest revision as of 08:23, 18 July 2012

You can find the number of different values using COUNT with DISTINCT

In 1915 four prizes were awarded in three different subjects:

SELECT yr, subject, winner
  FROM nobel
 WHERE yr=1915

COUNT(subject) gives 4; COUNT(DISTINCT subject) gives 3.

SELECT COUNT(subject), COUNT(DISTINCT subject)
  FROM nobel
 WHERE yr = 1915

SELECT COUNT(subject), COUNT(DISTINCT subject)
  FROM nobel
 WHERE yr = 1915

@@ Line 5: / Line 5: @@
    <p>You can find the number of <i>different</i> values using COUNT with DISTINCT</p>
    <p>In 1915 four prizes were awarded in three different subjects:</p>
-<table><td><pre>SELECT yr, subject, winner
+<table class='NoBorder'><td><pre>SELECT yr, subject, winner
    FROM nobel
   WHERE yr=1915</pre>
 </td><td>
-<table border="1" class="restable" style=""><tr>
+<table border="1" class="Bordered" style=""><tr>
 <th>yr</th>
 <th>subject</th>