I have a sqlite database and I use System.Data.SQLite in my C# project.

My request is :

```
SELECT d1.* FROM DYN_table as d1 INNER JOIN ( SELECT id_bill, ordre_phase, type, MAX(valeur) maximum FROM DYN_table   WHERE id_customer=347 AND type IN (1,5,2)  GROUP BY id_bill, ordre_phase, type) as d2 ON d1.type = d2.type AND d1.valeur = d2.maximum AND d1.ordre_phase=d2.ordre_phase AND d1.id_bill=d2.id_bill WHERE d1.id_customer=347 AND d1.type IN (1,5,2) 

```

The request is working but I have the following Warning :

```
SQLite warning (284): automatic index on sqlite_sq_1E5A8EC0(id_bill)

```

When I try my request using "EXPLAIN QUERY PLAN" I see the last step is :

```
SEARCH SUBQUERY 1 AS d2 USING AUTOMATIC COVERING INDEX (id_bill=? AND ordre_phase=? AND type=?)

```

But there is an index for id\_bill in this table, all the indexes I have :
-Primary Key : id\_player, id\_bill, ordre\_phase, type
-type
-id\_player
-ordre\_phase
-id\_competition

I've tried to create an index with id\_bill, ordre\_phase and type but still the same "USING Automatic covering index" in the analyze.

Am I missing something ?