title: substring of variable length
body: <p>I have a table with a column which contains strings like below. </p>
  
  <pre><code>RTSPP_LZ_AEN
  RTSPP_LZ_CPS
  RTSPP_LZ_HOUSTON
  RTSPP_LZ_LCRA
  RTSPP_LZ_NORTH
  RTSPP_LZ_RAYBN
  RTSPP_LZ_SOUTH
  RTSPP_LZ_WEST
  RTSPP_BTE_CC1 
  RTSPP_BTE_PUN1 
  RTSPP_BTE_PUN2
  </code></pre>
  
  <p>I need to get the substring from the second occurrence of <code>_</code> till the end of string and as you can see the substring is not of fixed length. The first part is not always fixed it can change. As of now I am using the following code to achieve it. </p>
  
  <pre><code>SELECT SUBSTRING([String],CHARINDEX('_',[String],(CHARINDEX('_',[String])+1))+1,100)
  FROM [Table]
  </code></pre>
  
  <p>As you can see I am taking an arbitrary large value as the length to take care of variable length. Is there a better way of doing it?</p>