我在SQLite中运行的查询速度慢（2500+ ms）。这是EXPLAIN：
sqlite> .explain
sqlite> explain SELECT DISTINCT vino_maridaje.ID_maridaje, maridaje_texto
...> FROM maridaje
...> LEFT OUTER JOIN vino_maridaje ON vino_maridaje.ID_maridaje = maridaje.ID AND maridaje.ID_categoria = 1
...> LEFT OUTER JOIN maridaje_texto ON maridaje_texto.ID_maridaje = maridaje.ID AND maridaje_texto.ID_idioma = 1
...> LEFT OUTER JOIN vino ON vino.ID = ID_vino
...> WHERE vino.ID_pais = 1 AND vino.ID_tipo = 6 AND activo = 1
...> ORDER BY maridaje_texto;
addr opcode p1 p2 p3 p4 p5 comment
---- ------------- ---- ---- ---- ------------- -- -------------
0 Init 0 83 0 00
1 SorterOpen 4 3 0 k(1,B) 00
2 OpenEphemeral 5 0 0 k(2,B,B) 08
3 OpenRead 0 718 0 2 00
4 OpenRead 1 1586 0 3 00
5 OpenRead 6 2794 0 k(2,nil,nil) 00
6 OpenRead 2 726 0 4 00
7 OpenRead 7 3698 0 k(2,nil,nil) 00
8 OpenRead 3 1412 0 20 00
9 Rewind 0 67 0 00
10 Integer 0 1 0 00
11 Rowid 0 2 0 00
12 IsNull 2 62 0 00
13 SeekGE 6 62 2 1 00
14 IdxGT 6 62 2 1 00
15 IdxRowid 6 3 0 00
16 Seek 1 3 0 00
17 Column 0 1 4 NULL 00
18 Integer 1 5 0 00
19 Ne 5 61 4 (BINARY) 6c
20 Integer 1 1 0 00
21 Integer 0 6 0 00
22 Integer 1 7 0 00
23 SeekGE 7 57 7 1 00
24 IdxGT 7 57 7 1 00
25 IdxRowid 7 8 0 00
26 Seek 2 8 0 00
27 Column 2 1 4 NULL 00
28 Rowid 0 5 0 00
29 Ne 5 56 4 (BINARY) 6b
30 Integer 1 6 0 00
31 Integer 0 9 0 00
32 Column 1 1 10 NULL 00
33 MustBeInt 10 53 0 00
34 NotExists 3 53 10 00
35 Integer 1 9 0 00
36 Column 3 7 5 NULL 00
37 Ne 11 53 5 (BINARY) 6c
38 Column 3 5 4 NULL 00
39 Ne 12 53 4 (BINARY) 6c
40 Column 3 19 13 NULL 00
41 Ne 11 53 13 (BINARY) 6c
42 Column 6 0 14 NULL 00
43 Column 2 2 15 NULL 00
44 Found 5 53 14 2 00
45 MakeRecord 14 2 16 00
46 IdxInsert 5 16 0 00
47 MakeRecord 14 2 16 00
48 Column 2 2 18 NULL 00
49 Sequence 4 19 0 00
50 Move 16 20 1 00
51 MakeRecord 18 3 17 00
52 SorterInsert 4 17 0 00
53 IfPos 9 56 0 00
54 NullRow 3 0 0 00
55 Goto 0 35 0 00
56 Next 7 24 1 00
57 IfPos 6 61 0 00
58 NullRow 2 0 0 00
59 NullRow 7 0 0 00
60 Goto 0 30 0 00
61 Next 6 14 1 00
62 IfPos 1 66 0 00
63 NullRow 1 0 0 00
64 NullRow 6 0 0 00
65 Goto 0 20 0 00
66 Next 0 10 0 01
67 Close 0 0 0 00
68 Close 1 0 0 00
69 Close 6 0 0 00
70 Close 2 0 0 00
71 Close 7 0 0 00
72 Close 3 0 0 00
73 OpenPseudo 8 16 2 00
74 OpenPseudo 9 21 3 00
75 SorterSort 4 82 0 00
76 SorterData 4 21 0 00
77 Column 9 2 16 20
78 Column 8 0 14 20
79 Column 8 1 15 00
80 ResultRow 14 2 0 00
81 SorterNext 4 76 0 00
82 Halt 0 0 0 00
83 Transaction 0 0 311 0 01
84 TableLock 0 718 0 maridaje 00
85 TableLock 0 1586 0 vino_maridaje 00
86 TableLock 0 726 0 maridaje_texto 00
87 TableLock 0 1412 0 vino 00
88 Integer 1 11 0 00
89 Integer 6 12 0 00
90 Goto 0 1 0 00
这是EXPLAIN QUERY PLAN：
0 0 0 SCAN TABLE maridaje
0 1 1 SEARCH TABLE vino_maridaje USING INDEX idx_vino_maridaje_index_ID_maridaje (ID_maridaje=?)
0 2 2 SEARCH TABLE maridaje_texto USING INDEX idx_maridaje_texto_index_ID_idioma (ID_idioma=?)
0 3 3 SEARCH TABLE vino USING INTEGER PRIMARY KEY (rowid=?)
0 0 0 USE TEMP B-TREE FOR DISTINCT
0 0 0 USE TEMP B-TREE FOR ORDER BY
正如您所看到的，表格已经有了适当的索引。那么如何才能更快地进行查询呢？