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Data Query is a SQL-based Data Provider. This means it relies on SQL queries to select data that is then transformed into a recordset-type SDS. Data Query hides all the handling of the TYPO3- specific fields (deleted flag and enable fields) and also transparently handles language overlays.
It can receive filtering information from a Data Filter, which is transformed into SQL syntax.
Google Query is a Data Provider based on Google Mini or Google Search Appliance. It actually contains two providers, one returning recordset-type SDS (which acts as a Primary Provider with the displaycontroller) and one returning idlist-type SDS (which acts as a Secondary Provider with the displaycontroller).
This Data Provider is based on the Tag Pack extension. It uses tags to make selections of records from various tables and returns the keys to those records in a idlist-type SDS. It can act as a Secondary Provider with the displaycontroller.
The Tag Pack Provider does not interact with Data Filters.
A simple Data Provider where one could select a TYPO3 table and one or more records from that table, without having to write any SQL. It would return a recordset-type SDS with all fields from the selected table.