title: SQL query : how to check existence of multiple rows with one query
body: <p>I have this table <code>MyTable</code>:</p>
  
  <pre><code>PROG    VALUE
  -------------
  1       aaaaa
  1       bbbbb
  2       ccccc
  4       ddddd
  4       eeeee
  </code></pre>
  
  <p>now I'm checking the existence of a tuple with a certain id with a query like</p>
  
  <pre><code>SELECT COUNT(1) AS IT_EXISTS
  FROM MyTable
  WHERE ROWNUM = 1 AND PROG = {aProg}
  </code></pre>
  
  <p>For example I obtain with aProg = 1 :</p>
  
  <pre><code>IT_EXISTS
  ---------
     1
  </code></pre>
  
  <p>I get with aProg = 3 :</p>
  
  <pre><code>IT_EXISTS
  ---------
     0
  </code></pre>
  
  <p>The problem is that I must do multiple queries, one for every value of PROG to check.</p>
  
  <p>What I want is something that with a query like </p>
  
  <pre><code>SELECT PROG, ??? AS IT_EXISTS
  FROM MyTable
  WHERE PROG IN {1, 2,3, 4, 5} AND {some other condition}
  </code></pre>
  
  <p>I can get something like </p>
  
  <pre><code>PROG     IT_EXISTS
  ------------------
     1        1
     2        1
     3        0
     4        1
     5        0
  </code></pre>
  
  <p>The database is Oracle...</p>
  
  <p>Hope I'm clear</p>
  
  <p>regards </p>
  
  <p>Paolo</p>