Create a new Column incorporating part of the information from 2 columns + numbers

Trying to create a column with the Code numbers of the following sample table:

 New Code column need to create\replace for record 009985 should be:

LANME000 - 8-DIGIST LONG; (FIRST 3-LETTERS OF THE PAT_LAST + 2 LETTERS OF THE PAT_FIRST + 3-ZEROS).  All the records must be the same way.

However, if SECOND record with the same PAT_LAST & PAT_FIRST comes across, then it should be LANME001 (increased by one digit up to 999)

This is a long table.

 Wondering is this process is possible with excel\SQL statement or any other way?

 Any help will be appreciated.