Starting from Power BI Connector 1.5.5 export of Database View functionality was added.
This option is avaliable only for ServiceNow Admin only.
Database View can be added on data source page.
Click on Add Source button and select database view from the list:
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When Databse View is added it is possible to select fields (Referenced fields included), set Use display value option, set Filter string to get more accurate data.
Also all general options and fields are supported to set on data source with database view(s), such as Name, Description, Rows Limit, Use field labels for column names, Disable editing for other users.
To export data from database view general proccess for data exporting to PBI can be used (described in article)