title: how to collect multiple values as a single string in postgres?
body: <p>I have tables :</p>
  
  <pre><code>Project table
  
  id name
  -------
  1  A
  2  B
  
  Assignment table
  
  id name project_id
  -------------------
  1  A1   1
  2  A2   1
  3  A3   2
  </code></pre>
  
  <p>I wish to write a query that returns each project with the name of the assignments created from it, like :</p>
  
  <pre><code>project_id  assignments
  -----------------------
  1            A1,A2
  2            A3
  </code></pre>
  
  <p>Is there any way to achieve that ?</p>