title: Switch partition in SQL Server
body: <p>I have a table with partitions. Only the first partition contains data for 4 months, the other partitions by day, the partition set as left.</p>
  
  <p>I want to split the first partition by day to, the boundary is 4/2/2016 until 15/5/2016.</p>
  
  <p>My question is: should I switch from the left or from right? </p>
  
  <p>For example if I switch to 5/2/2016, the system write to 4/2/2016 (only a day) or write to the the second 5/2/2016-15/5/2016 </p>
  
  <p>Thanks</p>