title: ADD_MONTHS sql query in oracle 12c
body: <p>I am trying to implement the following SQL query</p>
  
  <pre><code>select SOURCE_SYSTEM,
         START_DATE,
         OWNER,
         SUMMARY,
         DETAIL 
    from CICUSTEXP.ACTIVITIES 
   where SOURCE_PARENT_ID = '001o0000006P8JH' 
     AND START_DATE &gt;= ADD_MONTHS(SYSDATE, -1) 
   ORDER BY START_DATE DESC;
  </code></pre>
  
  <p>Here <code>STARTDATE</code> is of type <code>TIMESTAMP(6)</code>. Now I want to get data based on the months that I would be passing, if I want to have data for the last 3 months what should I be passing in here? Or if want to have data for the next 12 months starting from today what should I be passing from here. I am quite confused.</p>
  
  <p>Update:
  From the Conversations below I have the following query to fetch data for the next 12 months. Not sure if they are correct.</p>
  
  <pre><code>select SOURCE_SYSTEM,
         START_DATE,
         OWNER,SUMMARY,
         DETAIL 
    from CICUSTEXP.ACTIVITIES 
   where SOURCE_PARENT_ID = '001o0000006P8JH' 
     AND START_DATE BETWEEN ADD_MONTHS(SYSDATE, 0) AND ADD_MONTHS(SYSDATE, 12) 
   ORDER BY START_DATE DESC;
  </code></pre>
  
  <p>And for fetching data for the last 3 months I have the following query.</p>
  
  <pre><code>select SOURCE_SYSTEM,
         START_DATE,
         OWNER,SUMMARY,
         DETAIL 
    from CICUSTEXP.ACTIVITIES 
   where SOURCE_PARENT_ID = '001o0000006P8JH' 
     AND START_DATE BETWEEN ADD_MONTHS(SYSDATE, -3) AND ADD_MONTHS(SYSDATE, 0) 
   ORDER BY START_DATE DESC;
  </code></pre>