I am trying to create regular expressions using metacharacters, but either I am doing something wrong or something isn't working. My understanding is that the results of a regular expression check will produce the records where the regular expression is not matched.
As an example of what I am doing: I have a test feature class with a field that has 16 of the same value (ACEC), 2 of another (Inholding) and 2 nulls. I think that using the expression ^[AC] should produce the records that do not begin with "AC". Thus, there should be 4 records in the results (the 2 "Inholding" and 2 nulls). Instead the check results show all 20 records.
I have tried this with a variety of metacharacters, and have had no luck with any. Is there something that I am not doing correctly, or am I misunderstanding how to use these characters in a regular expression query?