Get last value from user defined varchar field

HI All,

           I have a user defined varchar field  'TS_USER_01'. This field usually contains numbers. 

How do i write a logic to get the last value or the largest value from this field.

For example - If TS_USER_01 has series of values from 1 to 10, then i want the output to be printed as 10.

How do i achieve this logic in script Editor under Test Plan.