sql - 在 SQLite3 中，这个 select 语句会受益于两个索引吗？

Question

我在内存数据库中使用 DBD::SQLite。我为一个表定义了以下索引:

CREATE INDEX x ON ss (a, b);
CREATE INDEX y ON ss (c, d, e, o);

下面的select语句会用到这两个索引吗？

SELECT f, g
FROM ss
WHERE a = ? AND b = ? AND c = ? AND d = ? AND e = ?

而且，我应该只在 where 子句中的那些列上创建索引吗？

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我问这个只是因为我想用最少的 INDEX 运行更多的 SELECT。

SELECT f, g FROM ss WHERE o = ?
SELECT f, g FROM ss WHERE a = ? AND b = ?
SELECT f, g FROM ss WHERE c = ? AND d = ? AND e = ?
SELECT f, g FROM ss WHERE c = ? AND d = ? AND o = ?
SELECT f, g FROM ss WHERE a = ? AND b = ? AND c = ? AND d = ? AND e = ?

Answer 1

使用EXPLAIN QUERY PLAN ( http://sqlite.org/lang_explain.html ) 查看使用了哪些索引。

EXPLAIN QUERY PLAN
SELECT f, g
FROM ss
WHERE a = ? AND b = ? AND c = ? AND d = ? AND e = ?

结果类似

"0","0","TABLE ss WITH INDEX ..."