sql - substring of variable length

Question

I have a table with a column which contains strings like below.

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

I need to get the substring from the second occurrence of _ 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.

SELECT SUBSTRING([String],CHARINDEX('_',[String],(CHARINDEX('_',[String])+1))+1,100)
FROM [Table]

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?

Answer 1

You can use CHARINDEX in combination with REVERSE function to find last occurrence of _, and you can use RIGHT to get the specified number of characters from the end of string.

SELECT RIGHT([String],CHARINDEX('_',REVERSE([String]),0)-1)

SQLFiddle DEMO