• margin1 : A nonnegative integer that specifies the number of characters on the left end of the string to mask. If the value is 0, no left end characters are masked. 

• margin2 : A nonnegative integer that specifies the number of characters on the right end of the string to mask. If the value is 0, no right end characters are masked. 

• mask_char : (Optional) The single character to use for masking. The default is ’X’  if mask_char  is not given. 

The masking character must be a single-byte character. Attempts to use a multibyte character produce an error. 

Return value: 

The masked string, or NULL  if either margin is negative. 

If the sum of the margin values is larger than the argument length, the entire argument is masked. 

Example: 

mysql> SELECT mask_outer(’abcdef’, 1, 2), mask_outer(’abcdef’,0, 5); +----------------------------+---------------------------+ | mask_outer(’abcdef’, 1, 2) | mask_outer(’abcdef’,0, 5) | +----------------------------+---------------------------+ | XbcdXX | aXXXXX | +----------------------------+---------------------------+ mysql> SELECT mask_outer(’abcdef’, 1, 2, ’*’), mask_outer(’abcdef’,0, 5, ’#’); +---------------------------------+--------------------------------+ | mask_outer(’abcdef’, 1, 2, ’*’) | mask_outer(’abcdef’,0, 5, ’#’) | +---------------------------------+--------------------------------+ | *bcd** | a##### | +---------------------------------+--------------------------------+ 

## • mask_pan( str ) 

Masks a payment card Primary Account Number and returns the number with all but the last four digits replaced by ’X’  characters. 

Arguments: 

• str : The string to mask. The string must be a suitable length for the Primary Account Number, but is not otherwise checked. 

Return value: 

The masked payment number as a string. If the argument is shorter than required, it is returned unchanged. 

Example: 

mysql> SELECT mask_pan(gen_rnd_pan()); +-------------------------+ | mask_pan(gen_rnd_pan()) | +-------------------------+ | XXXXXXXXXXXX9102 | +-------------------------+ mysql> SELECT mask_pan(gen_rnd_pan(19)); +---------------------------+ | mask_pan(gen_rnd_pan(19)) | +---------------------------+ 

