The Substring masking format extracts a portion of the original column value, and uses that to replace the original value. This masking format is similar to the SUBSTR database function.


  • Start Position: The starting position in the original string from where the substring should be extracted. The start position can be either a positive or a negative integer. If the start position is negative, the counting starts from the end of the string.
  • Length: The number of characters that you want in the substring. It should be an integer and greater than zero.

Supported Data Types

  • Character


  • Combinable: Yes
  • Deterministic: Yes
  • Reversible: No
  • Uniqueness: No


Suppose an original column value is abcd. A substring with a start position of 2 and length of 3 generates a masked string of bcd. A substring with start position of -2 and length of 3 generates a masked string of cd.