I’m migrating away from Google Sheets, so far with a lot of success, but I miss certain functions that at not included in the latest version of Calc. e.g =QUERY.
Query is a powerful function that I am finding it impossible to replicate with other functions that come with Calc
You would need the help of Base for this. It is possible to have a spreadsheet as datasource of an odb. Then you can query this datasource and drag the queries in other spreadsheets.
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Not so powerful as using a true database, but if someone want’s to do it this way…
Thanks 
looks like It’s been there for a while. Hope someone picks it up and adds it soon so I can leave Google Sheets.
Some time ago, I played around with HSQLDB in-memory databases. You have to have Java installed for that.
This enables you to use any valid SQL clause, including join between tables. No need to create a separate .odb file.
Basic procedure is:
Define names for the data you want to use as SQL Tables
Format the header cells with the right format. HSQLDB is using that format for the data type. Currently supported is @ (text), Boolean, and numeric.
The rest is described in the sheet AnalysisStadtKreisLand
For non-German users: The raw data are a lists of Stadt (=town), Kreis (= county), and Land (=state) from Germany
Maybe a bit overkill …
inline-database - posted.ods (221.3 KB)