SQL View, using the SharePoint Object Model API, searches for and displays all the lists from the top-level site (where the web part is installed) to all its sub sites. The user can only see the lists that he/she has permission to access. The user can then select the fields within the list to be included in the SQL query statement, including external fields referenced by a lookup field.
A SQL query statement is generated for the selected fields, which can then be copied and pasted to a report tool, or a SQL View can be created automatically in the SQL database to be used by the report tool.