I am trying to validate a list of email addresses in our database based upon a set of rules provided to us by the ISP. All the rules deal only with the localpart (username) portion of the email address. I imagine it has to be done with regex but I have no idea how to use regular expressions, so help in this matter is greatly appreciated.
what I have so far is this:
update emaillist set status = 'I' where substring(email,0,instr(email,'@') - 1) REGEXP <regex with rules here>
The rules are as follows:
1. The local part of the email address cannot be less than 3 characters nor greater than 16.
2. The local part of the email address cannot start with numbers.
3. The local part of the email address cannot contain any punctuation at all. no periods, dashes, hyphens, etc.