Understand now. Thanks Lutz & Gunter.


________________________________
From: sqlite-users <sqlite-users-boun...@mailinglists.sqlite.org> on behalf of 
Hick Gunter <h...@scigames.at>
Sent: Thursday, November 23, 2017 4:40:16 PM
To: 'SQLite mailing list'
Subject: Re: [sqlite] [EXTERNAL] help with EXPLAIN QUERY PLAN

COVERING INDEX means that all required fields for the query can be read from 
the index alone, without accessing the row itself.

-----Ursprüngliche Nachricht-----
Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] Im 
Auftrag von x
Gesendet: Donnerstag, 23. November 2017 17:34
An: sqlite-users@mailinglists.sqlite.org
Betreff: [EXTERNAL] [sqlite] help with EXPLAIN QUERY PLAN

Can anyone tell me why the detail column sometime states ‘USING INDEX ....’ and 
other time ‘USING COVERING INDEX ...’?

At first I thought USING COVERING INDEX implied the search was searching only 
the first m columns of an n column index (m less than n) but I’ve also seen 
USING COVERING INDEX when the query was searching all of the columns in the 
index.

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___________________________________________
 Gunter Hick | Software Engineer | Scientific Games International GmbH | 
Klitschgasse 2-4, A-1130 Vienna | FN 157284 a, HG Wien, DVR: 0430013 | (O) +43 
1 80100 - 0

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