How do I search for files of a specific type but do not contain certain words?

Question

Could you help me for a regex that would select ".xls", ".xlsx", ".csv" files but ignore files with "planning" or "CRM" in the file name.

Answer 1

Instead of using a regular expression I would recommend using the 'DOS Expression':

File Name: *.xls;*.xlsx;*.csv;NOT:planning;CRM