If you've used Excel or similar spreadsheet applications where one or more filters have been set up in worksheets, you already have a good idea of how filtering in NocTel Insight functions.
Filters in NocTel Insight function similarly to applying conditional filters to certain columns in an Excel worksheet - changing the selection in one column affects all the rows presented. In NocTel Insight, you never need to look at the underlying data source to see and apply the different dimensions and values to filter on as Insight does this for you due to its available data awareness.
In many cases it's possible to create a combination of filter selections that will cause no data to match the criteria. This phenomenon is known as mutual exclusivity. Mutual exclusivity means that something (data rows in this case) cannot match or be multiple conditions simultaneously. In this case, the conditions are the options selected (or de-selected) in NocTel Insight Report filters. A very simple example of mutual exclusivity would be to set the date in a Start Date filter to be after the date set in the End Date filter - it's impossible for the starting date of something to be after the date it ended.
In NocTel Insight there will be several filters which present an (All) option. Selecting this when one or more valid options are selected will cause every valid option to be selected. Selecting (All) again when all valid options are already selected will cause every option to be de-selected. When making selections and de-selections you will generally need to hit Apply for each separate filter to make it to effect. This is intentional as it is undesirable to have NocTel Insight attempt to process individual filter selections when all selections intended may not have been made yet.
Lastly, a useful function unique to filters is they are searchable when the control is presented as a multi-select dropdown. When the dropdown is selected, before the first enumerated option is listed there will be a text field noting "Enter search text". This search field is case insensitive, but does not perform any auto-correct or guestimation of valid matches in the event of misspelling.
In may cases applicable filters will include an Apply and Cancel button. If you select or de-select multiple values from the filter list, those changes will not be applied and the Report reprocesses the data until you've hit Apply. If you hit Cancel, your modifications to filter value selection will be discarded and the current view of the data will be unchanged.
Because Reports only utilize existing data from NocTel services, the data itself is immutable and cannot be modified or deleted from within NocTel Insight. If you ever find yourself in a position where the current Report view does not display anything and you are uncertain how to recover, simply refresh the web page and the Report's default View will be loaded.
Similarly, your personal view of a Report and any filter selections you've made are unique to you and do not affect other users who may be viewing the same Report at the same time.
Filters may be co-aware between Reports. You may encounter Filters in Reports from different Reporting Workbooks with similar titles and options. Only Reports within the same Reporting Workbook can be functionally co-aware of your selections. This does not apply across separate Reporting Workbooks.