You don't need any experience at all if you have a university degree. If you have a computer science degree, no work experience, you should have no problem getting a
TN for Systems Analyst.
The experience is only required if you have only a college diploma.
Your degree, job description, and TN category are all supposed to closely match. The further they stray from each other, the less likely it is you'll get the TN approved.
i.e. If you have a B.A. in History, haven't taken a large number of computer-related courses, have no work experience, and apply for a Systems Analyst, then you have very little chance. If you also have a bunch of years work experience as a Systems Analyst, then they might take that into consideration and it might push you a bit closer to getting it. All depends on who you get, in those border-line cases.