Not exactly an answer to the question, but I use a field named State, Status, or Condition.
VARCHAR(1), Default '' (an empty string).
I fill this field with a Char when the Status is "not normal", e.g.
e = ex client
i = ignore client (the client doesn't want any contact: e.g. client deceased)
u = undesirable (we don't want that client any more: payment problems, etc.)
For normal clients the clause is:
WHERE Status = ''
Active clients are found with a negative flag (Compare an empty string with zero)