title: Select entry with only one entry in many to many relationship
body: <p>Say I have a database table <code>user_provider</code>, that contains many to many relationship of <code>user</code> and <code>provider</code> table.<br>
  I want to get only those <code>userId</code> which is having only one provider</p>
  
  <pre><code> SELECT spr1.SU_URS_ID,count(spr1.SU_URS_ID)
   FROM overstappen.spr_usr spr1 
   WHERE spr1.SU_URS_ID in ( select spr.SU_URS_ID 
                             from overstappen.spr_usr spr 
                             where spr.SU_SPR_ID =40) 
   GROUP BY spr1.SU_URS_ID; 
  </code></pre>
  
  <p>Above query returns all users which is having <code>SU_SPR_ID 40</code>. And the total no of users with same userId in spr_usr table.</p>
  
  <p>I only want to get user with <code>count 1</code>. i.e user with only one provider.</p>
  
  <p>Thanks in advance.</p>