title: Concatenate three columns data into one column in Postgres
body: <p>Can anyone tell me which command is used for concatenate three columns data into one column in PostgreSQL database?</p>
  
  <p>e.g.</p>
  
  <p>If the columns are</p>
  
  <pre><code>begin | Month | Year
     12 |     1 | 1988
     13 |     3 | 1900
     14 |     4 | 2000
     15 |     5 | 2012
  </code></pre>
  
  <p>result like</p>
  
  <pre><code>Begin
  12-1-1988 
  13-3-1900
  14-4-2000
  15-5-2012
  </code></pre>